Euphorbia caput-medusae L. is clarified, with some notes added about its history and natural distribution.

Introduction

If there would be a contest for the most famous species of succulent Euphorbia, Euphorbia caput-medusae L. would be a good candidate. One factor that contributes to its candidacy: It is one of the earliest known succulent species of South Africa – already known in Europe in the late 17^th century. This species is found growing frequently on the Cape Peninsula and this is the place where the first Europeans set foot on land in southern Africa. The appearance of this plant, very unlike any European plant, must have stunned them. It can best be described as a head with snake-like branches. No less important for its fame is the very appealing name it received: Euphorbia caput-medusae, the Euphorbia with the head of Medusa. About the Greek mythological Medusa, who was cursed with her hair turned into snakes, one can easily write an article of its own. Tale tells that Perseus killed Medusa and flew with her head around the African Continent. Some drops of blood fell on the shores of the Cape of Good Hope which grew into Euphorbia caput-medusae.

Medusoid species of Euphorbia are taxonomically a difficult group of species. Some related species of Euphorbia caput-medusae L. were put into synonymy by Bruyns et. al. (2006) – an approach that  is discussed here in this paper. All species involved here are presented and their taxonomical status discussed.

Euphorbia caput-medusae

As early as 1753 Linnaeus established this species, but in doing so he included no less than five distinct species of Euphorbia. In these early days, the fact that a seed grown plant shows a very different habit than a plant grown from a branch has added much to the confusion and resulted in different species names.

Merely following N. E. Brown (1915), White, Dyer & Sloane (1941) state that the publication of Euphorbia caput-medusae L. was problematic and probably not according to the rules of Botanical Nomenclature but continue: “One must hope that the name of E. caput-medusae itself will never have to be invalidated, for it is extremely picturesque and descriptive.”

Still today, large medusoïd plants grow on the rocky slopes and in the coastal Sandveld of the Cape Peninsula in large numbers (Fig. 1). And yes, these plants still are referred to as Euphorbia caput-medusae, more than 75 years after White, Dyer & Sloan put their hope to paper.

Nevertheless, things have changed, as only recently P. V. Bruyns et al. (2006) sank seven species and one variety into synonymy under Euphorbia caput-medusae. As a consequence plants looking quite different from Euphorbia caput-medusae now bear the same name. Also the natural distribution of E. caput-medusae became largely extended from the stormy Cape Peninsula as far north as the arid and wind-swept borders of the Orange River into Namibia, mainly along the west coast of South Africa.

In this article the author presents the involved taxa, even though some are poorly known. Based on literature, the study of herbarium specimens and his observations from numerous travels to Euphorbia localities in South Africa, he will discuss, whether putting these species listed below into synonymy can be regarded as justified.

Taking the nomenclatural situation from White, Dyer & Sloane (1941) as a starting point, the seven species and one variety sunk into synonymy under Euphorbia caput-medusae by Bruyns et al. (2006) are:

• Euphorbia tuberculata
• Euphorbia tuberculata macowanii (N.E.Br.) A.C.White, R.A.Dyer & B.Sloane
• Euphorbia ramiglansE.Br.
• Euphorbia confluens Nel
• Euphorbia tuberculatoidesE.Br.
• Euphorbia marlothianaE.Br.
• Euphorbia muiriiE.Br.
• Euphorbia bolusiiE.Br.

Present taxonomical status according to Bruyns (2012):

Euphorbia caput-medusae L., Sp. Pl. 1: 452 (1753).

Holotype: J. Burm., Rar. Afric. Pl.: t. 8 (1738), designated by Wijnands (1983)

Euphorbia fructus-pini Mill., Gard. Dict. ed. 8: n.º 10 (1768).

Euphorbia medusae Panz., Vollst. Pflanzensyst. 14: 109 (1788).

Euphorbia caput-medusae var. geminata Aiton, Hort. Kew. 2: 136 (1789).

Euphorbia caput-medusae var. major Aiton, Hort. Kew. 2: 135 (1789).

Euphorbia caput-medusae var. minor Aiton, Hort. Kew. 2: 135 (1789).

Euphorbia tuberculata Jacq., Pl. Hort. Schoenbr. 2: 43 (1797).

Dactylanthes tuberculata (Jacq.) Haw., Syn. Pl. Succ.: 133 (1812).

Medusea fructus-pini (Mill.) Haw., Syn. Pl. Succ.: 134 (1812).

Medusea major Haw., Syn. Pl. Succ.: 134 (1812).

Medusea tessellata Haw., Syn. Pl. Succ.: 135 (1812).

Euphorbia commelini DC., Cat. Pl. Horti Monsp.: 110 (1813).

Treisia tuberculata (Jacq.) Haw., Suppl. Pl. Succ.: 65 (1819).

Euphorbia tessellata (Haw.) Steud., Nomencl. Bot. 1: 328 (1821).

Euphorbia fructus-pini var. geminata (Aiton) Sweet, Hort. Brit. 2: 356 (1826), not validly publ.

Medusea tuberculata (Jacq.) Klotzsch & Garcke, Monatsber. Königl. Preuss. Akad. Wiss. Berlin 1859: 251 (1859).

Euphorbia parvimamma Boiss. in A.P.de Candolle, Prodr. 15(2): 86 (1862).

Euphorbia bolusii N.E.Br. Fl. Cap. (Harvey) 5(2): 333 (1915).

Euphorbia macowanii N.E.Br. Fl. Cap. (Harvey) 5(2): 334 (1915).

Euphorbia marlothiana N.E.Br. Fl. Cap. (Harvey) 5(2): 331 (1915).

Euphorbia muirii N.E.Br. Fl. Cap. (Harvey) 5(2): 331 (1915).

Euphorbia ramiglans N.E.Br. Fl. Cap. (Harvey) 5(2): 306 (1915).

Euphorbia tuberculatoides N.E.Br. Fl. Cap. (Harvey) 5(2): 332 (1915).

Euphorbia confluens Nel, Kakteenkunde 1933: 193 (1933).

Euphorbia geminata (Aiton) Marloth ex A.C.White, R.A.Dyer & B.Sloane, Succ. Euphorb.: 355 (1941), nom. illeg.

Euphorbia tuberculata var. macowanii (N.E.Br.) A.C.White, R.A.Dyer & B.Sloane, Succ. Euphorb.: 372 (1941).

The description of Euphorbia caput-medusae is taken from White, Dyer & Sloane (1941) and is underlined where it is revised by the author.

Plant: a dwarf succulent, spineless but with persistent, green remains of the peduncles on the branches; main stem a continuation of the thickened main root, forming a globose body up to 15 or 20 cm. thick, partly buried in the ground, covered at the top except on a central branchless area with very numerous crowded branches, uniformly green, forming clumps up to 50 or 70 cm. in diameter; branches 1.7 to 2.5 cm. thick, cylindric or somewhat cylindric-clavate very obtuse, tuberculate, those at the centre erect and 5 to 10 cm. long, those at the circumference ascending-spreading or spreading and curving and 15 to 37.5 cm. long ; tubercles 5 to 8 mm. long, 3 to 5 mm. broad, 3 to 4 mm. prominent, obliquely conical, acute ;

Leaves: soon deciduous, 3 to 5 mm. long, 0.7 to 1 mm. broad, linear, acute or obtuse, thick and fleshy, flat or slightly concave-channelled above, very convex or obtusely keeled beneath;

Inflorescence: cyathia solitary, produced in clusters at the apex of the branches on peduncles arising from the axils of the tubercles ; peduncles 1 to 10 mm. long, stout, bearing 5 to 7 bracts, glabrous,  staying green and persistent after the seeds are expelled, then wither and shed; bract about 3 mm. long, broadly ovate or elliptic, obtuse ciliate ; involucre broadly and shallowly cup-shaped, 1.2 cm. or rather more in diameter, with 5 glands and 5 transversely oblong or subquadrate, connivent lobes, which are subtruncate and closely toothed at the top, glabrous on the back, pubescent on the inner face, red or purple, at least at their tips ; glands 3.5 to 4 mm. long and 2.5 to 6 mm. broad, palmately divided to half-way down into 3 to 6 linear processes entire or toothed at their tips, glabrous, with the undivided part green, minutely pitted, and the processes white ;

Pistillate flower: ovary sessile, obtusely 3-angled glabrous ; styles 2.5 to 3 mm. long, united into a column up to the middle or nearly to the top, with erect, shortly bifid tips, slightly exserted beyond the lobes of the involucre.

Type locality: Cape Prov.: without precise locality.

Distribution: Cape Distr.: mountains near Cape Town; Lion’s Head; shore near Green Point; etc. Extending north and east of Strandfontein.

Euphorbia tuberculata

Present taxonomical status according to The World Plant Checklist (2019): Synonym of Euphorbia caput-medusae L.

Both Euphorbia caput-medusae and Euphorbia tuberculata are relatively well-known taxa growing widespread in the Western Cape, quite often in close range of densely populated areas. Euphorbia caput-medusae grows mainly on the Cape Peninsula and Euphorbia tuberculata grows in the adjacent area to the north, for instance with large populations around Clanwilliam and at the shores near Lambert’s Bay. Both are also large plants and among the largest of the medusoïd species. At first glance Euphorbia tuberculata resembles Euphorbia caput-medusae very closely in habit. It is safe to assume these two species are most closely related and the other species mentioned in the list of synonymous taxa are more remotely related. This implies that if these two species have been put into synonymy undeservedly, the other taxa are also undeservedly synonymised.

In order to answer the question whether these two taxa are different, we must have a close look at them: White, Dyer & Sloane (1941) make only one small remark about possible differences between Euphorbia caput-medusae and Euphorbia tuberculata (see below), while in contrast to this minor remark there is quite a lengthy debate about differences of species like Euphorbia pugniformis Boiss., E. woodii N.E.Br., E. inermis Mill. and E. esculenta Marloth. The reason for this might very well be that in the old days Euphorbia caput-medusae was a poorly understood species and that its taxonomic history was doubtful.

White, Dyer & Sloane (1941, p. 359) say: “The glands of E. caput-medusae show a striking contrast of color; their united basal part is green, the processes are white. This contrast, taken in conjunction with the similar shape of the main stem, shows the affinity which the species bears to E. tuberculata Jacq. and its allies”. In other words, the main stem and the glands of the two species look the similar.

Based on personal observations I would say that the main stem of Euphorbia tuberculata is less developed and, except as a young plant, it is buried in the sand.

Euphorbia tuberculata always grows on flat areas in deep loose sandy soil that allows the main stem to retract in the soil. Euphorbia caput-medusae extends its range to slopes, sometimes even quite steep or on nearly bare rocks. The picture by Ernst van Jaarsveld in the article by Daryl Koutnik (1987, page 80) is a good example of this and, in my opinion, one of the most spectacular Euphorbia pictures ever taken. In fact Euphorbia caput-medusae is the only species mentioned in this present text that grows on rocky slopes. All other species included (except Euphorbia bolusii N.E.Br. and Euphorbia muirii N.E.Br., because of lack of information) are always found growing on the flats in deep sandy soil.

The other feature White, Dyer & Sloane mention is the glands with their contrasting colours. Both species have such glands, but there is a minor difference: In Euphorbia caput-medusae the green of the basal part has a straighter line towards the processes (see Fig. 2). In Euphorbia tuberculata this line is jagged and sometimes the incision between the processes runs into the green, as can be seen in Fig. 5. However, this difference is not found in all plants and can hardly serve as a feature to separate plants as different taxa. However the processes are more developed, branch more frequently and are a little bit larger in Euphorbia tuberculata.

One remark about the branches of Euphorbia caput-medusae must also be made here: The lateral branches can be extremely variable. The cause for this could very well be the growing conditions the plant has to endure. In cultivation branches are produced mostly with tubercles stretched lengthwise, over 1 cm long and arranged in only 8 rows. Such plants can be found in nature as well. But one can find also plants with nearly rounded, much sharper tubercles arranged in as many as 20 rows.

In the species description of Euphorbia caput-medusae, White, Dyer & Sloane (1941, p. 352) copy N. E. Brown (1915) when they describe the peduncles: “1 to 10 mm. long, stout, bearing 5 to 7 bracts”. About Euphorbia tuberculata they write: “peduncles 0,5 to 2 cm. long, spreading or ascending, somewhat flattened on the upper face, bearing 4 bracts under the involucre at the apex, glabrous, elongating as the capsule ripens to about 5 cm. and ultimately hardening and persisting” (p. 369). Comparing these notes about the peduncles of both species, several remarks must be made:

– The peduncles of Euphorbia caput-medusae are much shorter than those of Euphorbia tuberculata, however, it is not said whether or how much peduncles of Euphorbia tuberculata elongate after flowering. This elongating of the peduncles is very dubious in my opinion. On all the pictures I have taken myself or I have seen, one can see the peduncles of the flowers are just as long as the woody and persistent peduncles on the older parts of the branches (see Fig. 6). I have seen plants in nature with quite short peduncles of about 2 cm, but a length of the peduncles of about 4 to 5 cm is most frequent.

– The term “stout” is used by White, Dyer & Sloane, when they give the brief descriptions of the peduncles of Euphorbia caput-medusae. Indeed, the peduncles of Euphorbia caput-medusae are thicker and straight. Also they stay green for more than one season, a feature I have never noticed in Euphorbia tuberculata. This phenomenon can be clearly seen on  the magnificent drawing of  Matilda Smith in Curtis’s Botanical Magazine (1916) (see Fig. 7).

– In the description of the peduncles of Euphorbia tuberculata the term “ascending” is used, which I read as “bending upwards”, which they mostly do. However, I have noticed that sometimes they can bend downwards as well (as you can see in Fig. 5). Still, when observing a flowering branch, one notices most peduncles are bent. After maturity they bend even more, sometimes they can even have a curly look. Fig. 6 shows a flowering plant of Euphorbia tuberculata, from near Graafwater. Here you can see the cyathia of this season and the old mature peduncles of the two seasons before. The length of the peduncles is not very much different and you can also see that during ageing the bending proceeds.

– The number of the bracts is 5 to 7 in the case of Euphorbia caput-medusae and about 4 in Euphorbia tuberculata according to both N. E. Brown (1915) and White, Dyer & Sloane (1941).

Concluding the above one can say that the length, thickness, bending and ageing of the peduncles are different in each taxon. Still, the fact both N. E. Brown (1915) and White, Dyer and Sloane (1941) paid relatively little attention to the length and stoutness of the peduncles remains puzzling. For Euphorbia caput-medusae the length of the peduncles is given as 1-10 mm and for Euphorbia tuberculata 5-20 mm. In the case of the latter this length rather seems to be an exception, and 40-50 mm is most often encountered.

I have also visited numerous populations of Euphorbia tuberculata during periods of extreme drought and noticed that most of the plants had reacted to the lack of water and the heat by their branches becoming erect (see Fig. 8). I have seen this phenomenon in several populations of this species, but never in any other medusoïd Euphorbia.

To my knowledge Euphorbia caput-medusae grows not only naturally on the Cape Peninsula, but also more than 250 km to the north between Strandfontein and Doringbaai (see Fig. 3 and 4). Here plants grow in flat sandy soil, like Euphorbia tuberculata which is growing nearby. I noticed that plants of Euphorbia caput-medusae were growing flatter on the ground.

As I had never seen any reference to Euphorbia caput-medusae growing anywhere else than on the Cape Peninsula, I was in doubt about this identification for a long time, but the habit of the plants, their thick branches lying on the ground and their short peduncles led me to the conclusion that these plant should best be regarded as another population of Euphorbia caput-medusae. The fact that typical Euphorbia caput-medusae specimens grow within several hundreds of metres from typical Euphorbia tuberculata and maintain their own specific character is in fact a good indication we are dealing with two separate species. It seems there is something that prevents hybridizing.

Graham Williamson (2011a, 2011b) makes mention of considerable variation in seed morphology within the entire group and is most distinct regarding Euphorbia caput-medusae. I did not study the seeds of species involved, but this is another clue these plants sensu Bruyns don’t represent one single species.

In cultivation there is also a difference between these two species. Euphorbia caput-medusae is in general very easy to cultivate (Koutnik, 1987), a statement with which I fully agree. However Euphorbia tuberculata is more difficult to grow in our West European greenhouses. I must admit that this is not a very scientific proof of difference however.

Wijnands (1983) designated a drawing of J. Burman, published in 1738 as the type of Euphorbia caput-medusea L. In this picture we can clearly make out the stout main stem and the short peduncled, nearly sessile cyathia, typical for what is portrayed as Euphorbia caput-medusa in this paper (see Fig. 9).

Bruyns (2012) designated an illustration from Jacquin’s Plantarum rariorum horti caesari schoenbrunnensis descriptiones et icones (Jacquin, 1797) as the type for Euphorbia tuberculata Jacq. In this illustration we see a flowering seedling. A weak developed main stem and long peduncles are  clearly visible, the latter being twice as long as the main stem is thick. Again this picture is a good example of what is presented as Euphorbia tuberculata in this paper (see Fig. 10). Accordingly both species are well typified by their designated types.

The conclusion of the foregoing is that the peduncles clearly separate Euphorbia caput-medusae from Euphorbia tuberculata. Still, there is a palette of minor differences between these two as well, as the shape of the main stem and lateral branches, cyathia, behaviour during drought and cultural needs. Also the observation that populations of both species grow close to each other and yet they maintain differences supports this view. Based on these arguments Euphorbia caput-medusae and Euphorbia tuberculata should be regarded as distinct species:

Euphorbia tuberculata Jacq., Pl. Hort. Schoenbr. 2: 43 (1797).

Holotype: Jacq., Pl. Hort. Schoenbr. 2: 43 (1797), designated by Bruyns (2012)

Dactylanthes tuberculata (Jacq.) Haw., Syn. Pl. Succ.: 133 (1812).

Treisia tuberculata (Jacq.) Haw., Suppl. Pl. Succ.: 65 (1819).

Medusea tuberculata (Jacq.) Klotzsch & Garcke, Monatsber. Königl. Preuss. Akad. Wiss. Berlin 1859: 251 (1859).

The description of Euphorbia tuberculata is taken from White, Dyer & Sloane (1941) and is underlined where it is revised by the author.

Plant: a succulent with a stout, obconic main stem, wholly or partly buried in the ground, narrowed at the base, into a long thickened main root, which sometimes is bifurcated at the lower part, and producing from a apex many erect or decumbent branches, spineless but with persistent remains of the peduncles, ultimately forming clumps up to 75 cm. high ; branches thickened at the upper part, often 4 cm. thick, tuberculate, dull green or sometimes becoming whitish on the older parts ; tubercles in spiral series, rhomboid, more prominent in the younger specimens.

Leaves: produced at the flowering season and soon deciduous, 0.5 to 4 cm. long, about 1.5 mm. broad, erect or spreading-ascending, somewhat fleshy, linear, acute and recurved at the apex, channelled down the face, with incurved reddish margins, glabrous ;

Inflorescence: cyathia solitary, produced several together near the apex of the branches on peduncles arising from the axils of the tubercles ; peduncles 2 to 7 cm. long, spreading, often ascending, somewhat flattened on the upper face, becoming woody soon after shedding the fruit, bearing 4 bracts under the involucre at the apex, glabrous; bracts soon deciduous, 3.5 to 4 mm. long, about 3 mm. broad, elliptic-obovate, concave, obtuse, ciliate, glabrous ; involucre broadly bowl-shaped, up to 1.8 cm. in diameter including the processes of the glands, glabrous, with 5 glands and 5 subquadrate, toothed and minutely ciliate lobes ; glands separate, closely sessile on the cup of the involucre, about 3.5 mm. long, 5 mm. broad, broadly cuneate, palmatifid with 3 to 6 creamy processes, becoming crimson when ageing, which recurve at the apex, velvety greenish-brown on the upper surface.

Pistillate flower : ovary sessile and quite included in the involucre, densely pubescent with erect, somewhat bristle-like hairs ; styles exserted, up to 5 mm. long, united into a column nearly to the apex, with very short, slightly spreading, thickened tips ;

Capsule: sessile, 6 mm. long and as much in diameter, obtusely and somewhat deeply 3-lobed, with a distinct keel-like ridge on the back of each lobe, pubescent with longish white hairs or glabrous.

Type locality: South Africa, without precise locality.

Distribution: Cape Prov.: Namaqualand Distr.: between Driefontein and Heeren Logement ; etc. :

Van Rhynsdorp Distr.: Klaver : Paleisheuvel ; Clanwilliam Distr.: near Clanwilliam ; Lange Kloof ; Piquetberg Distr.: koppie near Het Kruis ; Malmesbury Distr.: between Mamre and Saldanha Bay.

Euphorbia tuberculata var. macowanii

I was not able to find any reference of Euphorbia tuberculata var. macowanii (N.E.Br.) A.C.White, R.A.Dyer & B.Sloane in recent succulent literature other than that it was listed as such in overviews until Bruyns et al. (2006) sunk it under Euphorbia caput-medusae. It is rather peculiar so little can be found about this variety, as its type-locality Clanwilliam is visited by many succulent enthusiasts.

Euphorbia macowanii was first published in the Flora Capensis ( N. E. Brown, 1915). White, Dyer & Sloane (1941) regarded the differences between Euphorbia tuberculata and E. macowanii as not enough to maintain it as a separate species, so they reduced it as a variety under the latter: Euphorbia tuberculata var. macowanii (N.E.Br.) A.C.White, R.A.Dyer & B.Sloane.

There were two collections cited by N. E. Brown (1915), namely Schlechter 8419 from near Clanwilliam, and MacOwan 3286 from Cannon Hill, Uitenhage Div. The latter collection was designated by Bruyns (2012) as the lectotype. But there are arguments that speak against designating this latter collection as the lectotype: N. E. Brown concluded MacOwan 3286 was mistakenly labelled as being collected from Cannon Hill, also this collection MacOwan 3286 is cited as mixed with pieces of Euphorbia tuberculata in the added notes by N. E. Brown when dealing with the latter species. As E. tuberculata does not grow on Cannon Hill,  the mixed collection of MacOwan 3286 cannot originate from Cannon Hill. Given that the origin of MacOwan 3286 is dubious, this makes Schlechter 8419 a better candidate for a lectotype.

However puzzling this may be, White, Dyer & Sloane did not seem to have any doubt about the identity of this plant, because Dyer found it again and collected new material, before publishing The succulent Euphorbieae (1941). White, Dyer & Sloane mentioned the area between Clanwilliam and Calvinia as its natural distribution, and I assume this is where Dyer collected the new material. Calvinia is over 150 km from Clanwilliam and the road is nearly entirely in the Great Karoo, when going through the Pakhuispas, where Euphorbia tuberculata has never been reported. Either R. A. Dyer collected this material close to Clanwilliam before he entered the Great Karoo through the Pakhuispas, or he first went to Calvinia on the road to Vanrhijnsdorp. Well north east of Vanrhijnsdorp I found other populations of plants similar to Euphorbia tuberculata, which are later discussed under divergent populations of Euphorbia tuberculatoides.

Euphorbia tuberculata var. macowanii differs from the typical variety by its overall smaller size. As most distinctive White, Dyer & Sloane (1941) mention the pubescent outer surface of the involucre and processes of the glands. It is impossible for me to find out whether plants similar to Euphorbia tuberculata with a pubescent involucre and glands grow, or have grown, in the vicinity of Clanwilliam. But if they do or did, it seems most likely they are part of one, or more, of the many populations of Euphorbia tuberculata growing in that area and as such contribute to the variability of this species.

Summarizing the information, seems inprobable that a distinct population of plants is growing near Clanwilliam with constant different characteristic features to justify taxonomic status as a variety. Accordingly Euphorbia tuberculata var. macowanii is not upheld as a variety of Euphorbia tuberculata.

Euphorbia tuberculata Jacq.: Pl. Hort. Schönbr., ii: 43, t. 208 (1797). stat. nov.

Synonyms:

Euphorbia macowanii N.E.Br., Fl. Cap. Harvey 5(2): 334 (1915).

Euphorbia tuberculata var. macowanii (N.E.Br.) A.C.White, R.A.Dyer & B.Sloane: Succ. Euph. Vol. 1: 372 (1941)

As stated before, Euphorbia tuberculata might very well be the linking species between Euphorbia caput-medusae and the other species listed in the introduction of this article. Therefore it is necessary to have a closer look at these.

Euphorbia ramiglans

White, Dyer & Sloane (1941) were unsure about the identity of Euphorbia ramiglans N.E.Br., a species again described by N. E. Brown (1915), based on a collection by H. Bolus in 1883. The collection consisted of only a few lateral branches, with no precise locality given other than ‘from Little Namaqualand’. No wonder the description of only these lateral branches made its true identity unsure for a long time. It remained so until Koutnik (1989) clarified the matter convincingly in his article “Euphorbia ramiglans N. E. Br. rediscovered?” In this article he showed that Bolus collected the type material 2 miles east of Port Nolloth. Even though the title is given with a question mark, Daryl Koutnik presented a strong case. This also corresponds well with White, Dyer & Sloane, who first distinguished Euphorbia ramiglans from Euphorbia woodii and its allies, and then linked it to plants growing in the coastal sand veld west of Springbok suggesting a close relationship to Euphorbia tuberculata.

In the description of Euphorbia ramiglans, N. E. Brown (1915) suggested it was probably similar to Euphorbia gorgonis Berger, but as we know now they are not closely related. The main characteristic features from this description are the absence of persistent peduncles, being 3 to 4 mm long, and the glands with the white filiform processes, being much branched at their tips.

The name “ramiglans” means “with branched glands”. This name is well given. The cyathia are not only very beautiful as they are relatively large, but also because the white filiform processes embrace them with a white ring and because the much branched processes give them a striking circular appearance (Fig. 13). All this makes the flower of Euphorbia ramiglans easily recognizable.

Plants fitting that description can be found easily in the coastal sandy plains east of Port Nolloth. I have visited this area several times and immediately noticed the huge variability in the habit of plants. Some were buried in the sand with only the tips of the branches visible. Others had a stout main stem raised above the soil, with long lateral branches, sometimes also re-branching (Figs 11 and 12). The length of the peduncles also varies from nearly sessile to about 10 mm. Peduncles do not wither immediately after the fruit has exploded. Withered peduncles may stay on the branches, but there are few or no peduncles of previous seasons to be found on the plants. The first time I visited this locality, most of the plants were fruiting and I saw plants with glabrous and others with pubescent fruits. This supports the view that plants here show a wide range of variation in several features.

Despite the fact that Euphorbia ramiglans was a poorly known species for so long, it is not rare at all in nature and occurs south and north of Port Nolloth in many large populations. It has also been reported from some 75 km south along the Atlantic shores at Kleinsee. I have not seen the plants there, but I received several pictures of specimens taken by Alma Moller. Plants look similar to the Port Nolloth plants and I include a photo here in order to make the overview as complete as possible (Fig. 14).

Even some 100 km more to the south, at Hondeklip Bay, I found similar plants quite easily in the coastal sands. However, the habitat was somewhat different, as bushes were growing at this locality (Fig. 15). The identification of these plants was not 100% certain, as I saw no specimens in flower. Nevertheless, the plants again were very similar to those seen at Port Nolloth.

To the north of Port Nolloth, the numerous populations around Alexander Bay are best-known, but in the Leach Archive quite a few pictures can also be found of LCL17662, taken at about half-way at Holgat River mouth. These plants match the ones from Port Nolloth and seem to be of the same size and grow mostly raised above soil level.

At the Orange River mouth in the area around Alexander Bay, Euphorbia ramiglans can be found at many localities, such as Bloukop, Grootderm and Swartbank. In general Euphorbia ramiglans is a smaller plant here and the branches are very short, quite frequently the lateral branches are even globular (Fig. 16). Also the well-developed main-stem grows in the soil and most plants are hardly elevated above soil-level. However, specimens can also be found growing above soil-level with longer lateral branches (Fig. 17). Another variation is that nearly all the plants have more rounded and flat tubercles, however also some have the sharper rhomboid tubercles. Even the persistence of the peduncles seems to be variable as some plants were found still carrying the woody remains of last seasons’ flower stalks (Fig. 18).

Euphorbia ramiglans also grows some 20 km inland along the shores of the Orange River to as far as just east of Beauvaillon. At this locality the plants grow a little bit larger and with longer lateral branches, but still smaller than the Port Nolloth plants. It seems quite likely that environmental conditions are the main cause for this variation as near the coast the coastal winds are most severe and it is most arid.

Finally, Euphorbia ramiglans is reported from north of the Orange River in Namibia.

Many populations of a slightly different medusoïd Euphorbia can be found along the coast between Port Nolloth and Alexander Bay. However plants from the Alexander Bay area in general are different in habit, although one can find plants of similar habit to the Port Nolloth plants. Even though most of the Alexander Bay plants look quite different in habit from the more southern populations of Euphorbia ramiglans there seems to be no constant characteristic feature to separate them taxonomically.

The remaining constant difference from Euphorbia tuberculata is its size and the cyathium with its much branched tips of the processes on the glands, so Euphorbia ramiglans N.E.Br. should be treated as a distinct species.

Taxonomical status:

Euphorbia ramiglans N.E.Br. Fl. Cap. (Harvey) 5(2.2): 306. (1915).

Type: South Africa, Namaqualand, 1883, H. Bolus sub BOL 9448.

Description of Euphorbia ramiglans taken from White, Dyer & Sloane (1941) and underlined where revised.

Plant: a dwarf succulent with an obconic main stem, wholly or partly buried in the ground, covered with branches at the top, except for a central branchless area, dull green to purple, forming clumps from 10 to 40 cm. in diameter ; branches, from globose to 20 cm. long, 1.2 to 2 cm. thick, sometime clavate, rarely re-branching, tubercled, glabrous; tubercles crowded, conical, rhomboid, 3 to 4 mm. prominent, tipped with a whitish leaf scar;

Leaves: produced in a small tuft at the apex of the branches, deciduous, 7 to 9 mm. long, linear, obtuse or subacute, channelled down the face, glabrous;

Inflorescence: cyathia solitary, produced at the tips of the branches, on peduncles arising from the axils of the tubercles; peduncles 3 to 4 mm. long, bearing 2 or 3 bracts, most frequently not persisting; bracts small and soon deciduous; involucre shallowly cup-shaped, 7 to 8 mm. in diameter, glabrous outside, with 5 glands and 5 erect, subquadrate, 2-toothed lobes; glands subcontiguous, spreading, 1.5 to 2.5 mm. in their greater diameter, transversely oblong, with 4 to 6 filiform processes along the outer margin, which are 1.3 to 1.5 mm. long and much branched at their tips;

Staminate flower: white, woolly, filling the involucre;

Pistillate flower: ovary sessile, sprinkled with rather long hairs; styles united to the top into a slender column 3.5 mm. long with spreading, cuneate and slightly bifid tips 0.7 mm. long.

Capsule: sessile, 5 mm. long and as much in diameter, obtusely 3-lobed, pubescent with longish white hairs or glabrous.

Type locality: Cape Prov.: Namaqualand Distr.: 2 miles east of Port Nolloth (Koutnik 1989).

Distribution: Along the coast of the Atlantic Ocean from Hondeklip Bay to Orange River mouth into Namibia.

Euphorbia confluens

Euphorbia confluens Nel was discovered in 1929 by H. Herre and four years later described by Nel (1933) based on plants found on an open plain near Kliphoogte in the Richtersveld. The re-branching of the lateral branches was pointed out by White, Dyer & Sloane (1941) as distinctive for this species. They also mention the nearly entire margin of involucre glands of young cyathia that later develop slender processes along the edges, but this feature is more or less appropriate for all species discussed in this article. The text about this species ends with the words; “Further information regarding this plant is much desired” (White, Dyer & Sloane, 1941, p. 379).

Even today the identity of Euphorbia confluens is somewhat unclear, but it is usually applied to plants found growing in the Richtersveld more inland and away from the coast where Euphorbia ramiglans is found. Several times, I have visited two populations of medusoïd Euphorbia referred to as Euphorbia confluens. One of them is on the flats south of Eksteenfontein and close to or even at the type locality (Fig. 19). The plants show the feature of re-branching lateral branches (Fig. 20). Especially in larger plants the re-branching is frequently observed, but far less frequent in younger plants.

However, the re-branching habit of Euphorbia confluens is not a feature to clearly separate it from Euphorbia ramiglans, as I also found re-branching specimens of E. ramiglans just east of Port Nolloth (Fig. 11).

Furthermore, plants from the flats south of Eksteenfontein can be characterized as somewhat larger than Euphorbia ramiglans from Port Nolloth and their branches are covered with persistent and longer peduncles at their tips while the cyathia are strikingly similar to those of Euphorbia ramiglans (Fig. 21).

In his Field Notes Books, Leach records this plant under LCL 17715, collected by Graham Williamson (GW 3924 and 3925), from Giais (Gras) Vlakte at Eksteenfontein. He adds “plants up to 1 meter in diameter and 0,2 meter high.” Also he identifies this plant as being similar to the population growing some 30 km east of Port Nolloth, the other locality I visited.

Hans Herre (1971) drew attention to Euphorbia confluens again many years after his discovery of this species in 1929. Herre referred to a population along the road from Eksteenfontein to Modderdrift, which is north of the type-locality, consisting of plants up to 1–2 m in diameter and of 0.5-0.75 m high. This is considerably larger than what is given in the type description of Euphorbia confluens as about 11 cm high and 35 cm in diameter. I have never seen such large medusoïd Euphorbia in the Richtersveld, but Herre must have known exactly what Euphorbia confluens was as he was the discoverer of the plant. So we must take into account Euphorbia confluens can grow much larger than what is thought. In fact, if such phenomenal medusoïd plants of 2 m in diameter and more than half a meter high do exist, they are by far the largest if all medusoïd species of Euphorbia.

The population mentioned before at about 30 km east of Port Nolloth is a fairly well-known and large population, which also grows in deep red sands (Fig. 22). The plants of this population are very much the same as the ones from south of Eksteenfontein, only the plants are a bit smaller and the frequency of re-branching plants is less. I can also find reference of the latter population several times in the Leach Archive. Oddly enough, Leach identified these plants as Euphorbia tuberculatoides N.E.Br., however adding a question mark. Euphorbia tuberculatoides is a species described from near Hopefield, roughly some 550 km to the south. I will discuss it later in this article.

Plants well-fitting the description Nel gave for Euphorbia confluens growing at or near its type-locality south of Eksteenfontein leave little doubt about their identity. However, the re-branching lateral branches with the persistent peduncles are features also found in populations of Euphorbia ramiglans, however much less frequently. The flowers are similar to the ones of Euphorbia ramiglans.

This makes it is difficult to maintain Euphorbia confluens Nel as a separate species from Euphorbia ramiglans N.E.Br. It is better if it is regarded as a variety of the latter, and a formal change is made here. However one must consider it can grow far larger than first described, as both Leach (the Leach Archive) and Hans Herre (1971) make mention of such large plants.

Euphorbia ramiglans N.E.Br. var. confluens (Nel) van Veldhuisen comb. nov. et stat. nov.

Basionym: Euphorbia confluens Nel: Kakteenkunde: 193 (1933).

Type: South Africa, Cape, open flats, Kliphoogte, Sept. 1929, Herre sub SUG 5549 (missing, Lectotype: Illustration in Kakteenkunde: 194 (1933).

Description of Euphorbia ramiglans var. confluens taken from White, Dyer & Sloane (1941).

Plant: a dwarf succulent, spineless but with persistent remains of the peduncles; main stem a continuation of the thickened main root, obconic, 9 to 11 cm. thick, partly buried in the ground and completely covered at the upper part to the centre with ascending-spreading branches, forming clumps about 11 cm. high and 30 to 35 cm. in diameter; branches cylindric, the inner ones straight, 3 to 4 cm. long, simple, the outer ones 17 to 18 cm. long, somewhat upcurved, with numerous small branchlets 0,8 to 1 cm. thick at the upper end, both the inner and outer branches about 2 to 2.5 cm. thick, tuberculate; tubercles hexagonal, 0,8 to 1 cm. broad, very prominent, tipped with a white leaf scar.

Leaves: produced in clusters at the apex of the branches, deciduous, sessile, 1.5 to 2 cm. long, 2 mm. broad, linear, grooved on the upper side, fleshy, glabrous.

Inflorescence: cyathia solitary, produced 6 or 7 at the apex of each branch on peduncles arising from the axils of the tubercles; peduncles 1 to 3.5 cm. long, ultimately persisting 1 or 2 years; bracts almost oblong, 3 mm. long, 5 mm. broad, dotted in red outside, ciliate with white hairs; involucre 1 to 1.5 cm. in diameter, sparsely covered with white hairs outside, with 5 glands and 5 subquadrate, fimbriate lobes, which are 1 mm. long, 2 mm. broad, yellow-green dotted with red, sparsely covered with short white hairs outside and glabrous inside; glands contiguous, spreading, 1 mm. long, 3 mm. broad, transversely oblong, green to yellow-green with a white margin and with 4 to 6 much-branched, hair-shaped, white processes 2 mm. long along the outer margin.

Staminate flowers: 7 mm. long, covered with long, white, silky hairs on the pedicel below the joint of the filament.

Pistillate flower: ovary sessile, 3 mm. in diameter, subglobose, covered with long, white, silky hairs : styles united into a cylindric column nearly to the apex, with thickened tips 1 mm. long.

Type locality: Cape Prov.: Namaqualand Distr.: Richtersveld: near Kliphoogte.

Distribution: Cape Prov.: Namaqualand Distr.: east of Port Nolloth.

Graham Williamson’s specimen number GW 3819

In his magnificent book “Richtersveld, the enchanted Wilderness” Graham Williamson (2000) presents Euphorbia tuberculata as a species that occurs mainly on the coastal plains east and north of Port Nolloth and in the central Richtersveld north of Lekkersing. Two pictures are added, the first one is of a flat medusoïd Euphorbia with very thick, densely tubercled branches and with a few young fruits developing on rather long peduncles (Fig. 23). This first picture we can find in The Leach Archive under the collection number GW 3819 and listed it as LCL 17673. The second picture shows a portion of a flowering plant with many long peduncled flowers, matching very much Euphorbia tuberculata from the Clanwilliam/Lambert’s Bay area. This second picture cannot be found in The Leach Archive.

GW 3819 was collected at about 15 km east of Port Nolloth. Also some notes are added: “largest plant 1,2 m. d., hairy capsules ? stem tubercles, cf. Euphorbia species 30 km. East of Port Nolloth”.

There are more pictures of GW 33819/LCL 17673 in the archive and another two are shown here (Figs 24 and 25). This plant in figure 24 bears flowers of the “ramiglans/confluens”-type with the much branched tips of the processes of the glands. The picture of the flowering plant shown in the second picture in Williamson’s book has long peduncles with less branched processes on the glands. It is my guess that the second picture in William’s book was not taken from plants at the locality east of Port Nolloth.

However I was very puzzled at first when reading about Euphorbia tuberculata growing in the Richtersveld and I am now convinced GW 3819 is in fact Euphorbia ramiglans var. confluens. Also the very large plants H. Herre (1971) found along the road from Eksteenfontein to Modderdrift can be referred to in this context.

The other population mentioned by Graham Williamson (2000) in the central Richtersveld, north of Lekkersing, is presented by him (Williamson 2011b) in more detail in Euphorbia World. Several colonies at about 30 to 35 km north of Lekkersing are described as what “appears to be Euphorbia tuberculata with a rather different growth form, different involucre glands, distinctly hairy velvety capsules and longer peduncles than seen in E. ramiglans” (Williamson, 2011b, page 5). The few lines are accompanied by two pictures of these plants, one is a single plant in habitat and the other one shows some flowers and fruits. I have never seen these plants and do not have any other record of them. They remind me also of Euphorbia filiflora, but for now they remain a mystery to me.

Euphorbia tuberculatoides

Euphorbia tuberculatoides was described by N. E. Brown in the Flora Capensis (1915). It received this name, meaning “The euphorbia looking like tuberculata”. Comparing it to Euphorbia tuberculata, Brown summarizes its differences as: more slender habit, shorter leaves, smaller involucre and glabrous ovary. Regarding the latter he adds that one specimen has a few weak hairs on the ovary. Also, the tubercles appear to be smaller, the involucre paler in colour when dried, its lobes smaller, more subquadrate, more finely toothed and apparently purple.

The species was described based on plants collected by Bachmann. The three collections involved are Bachmann 1042 (designated as lectotype by Bruyns, 2012) from south of Hopefield along the road to Theefontein, Bachmann 1043 from near Groene Kloof (Mamre) and Bolus 5349 without locality.

White, Dyer & Sloane (1941) merely repeated the remarks of N. E. Brown when discussing Euphorbia tuberculatoides, but concluded that the affinity between it and E. tuberculata is an extremely close one. Of the differing features, the glabrous ovary was emphasized as most important. It looks as if they favoured the opinion to reduce this species to varietal rank under Euphorbia tuberculata, but hesitated to do so because of lack of information, as apparently they had not seen this species themselves.

From my experience, a glabrous or a pubescent ovary or fruit is not a decisive feature to separate groups of plants as different species. Also I have observed specimens both with glabrous and with pubescent fruits in populations of Euphorbia tuberculata (see Figs 26 and 27).

Based on the arguments above it seems hard to maintain Euphorbia tuberculatoides N.E.Br. as a distinct species. However, there is one caveat: I never went to the area South of Hopefield in order to check whether large medusoïd plants are still growing there. The reason is this area is heavily cultivated nowadays and I have never found any recent reference to anybody found such plants there.

The distinguishing features between Euphorbia tuberculata and Euphorbia tuberculatoides make a weak case to maintain the latter as a separate species. But as long as the identity of Euphorbia tuberculatoides is not clear, it seems best to uphold it as species on its own, yet imperfectly known.

Euphorbia tuberculatoides N.E.Br., Fl. Cap. (Harvey) 5(2.2): 332 (1915).

Description of Euphorbia tuberculatoides taken from White, Dyer & Sloane (1941).

Plant: a succulent with a combined thickened main root and reduced main stem, nearly or wholly buried in the ground and producing numerous branches from its apex, spineless but with some persistent remains of the peduncles, ultimately forming clumps up to 45 cm. high; branches 1.2 to 1.7 cm. thick when dried, cylindric, tuberculate, glabrous; tubercles, arranged in several spiral series, rhomboid, shortly conical, 6 to 8 mm. broad, 2 to 3 mm. prominent.

Leaves: deciduous, 0.8 to 1 cm. long, 0.7 to 1 mm. broad, erect, linear, acute, channelled down the face, glabrous.

Inflorescence: cyathia solitary, produced in a cluster at the apex of the branches on peduncles arising from the axils of the tubercles; peduncles 0.6 to 3 cm. long, erect or ascending, glabrous, bearing 4 bracts under the involucre at the apex; bracts deciduous as the involucre opens, about 3 mm. long, 2 mm. broad, obovate or orbicular-obovate, concave, glabrous; involucre obconic-cup-shaped, about 1 cm. in diameter when dried, glabrous, with 5 glands and 5 orbicular-subquadrate, subentire or very minutely toothed lobes; glands separate, shortly or distinctly stalked, 3 to 3,5 long, 3.5 to 5 mm. broad, broadly cuneate, recurved at the sides and palmately divided by the middle into 3 to 5 linear segments, entire or bifid at their revolute tips, with the glandular area apparently dark red and the segments white.

Pistillate flower: ovary sessile, included in the involucre, 3-angled, glabrous; styles 5.5 to 7 mm. long, united into a column nearly to the apex, with erect, thickened, entire or bifid tips.

Type locality: Cape Prov.: Malmesbury Distr.: near Hopefield, on the road to Theefontein.

Distribution: Malmesbury Distr.: also at Grootfontein, near Mamre ; etc.

Uncertain identifications related to E. tuberculatoides

This quest for Euphorbia tuberculatoides does not end here. As stated above, this species received very little attention in succulent literature since White, Dyer & Sloane (1941). It was only pictured once in The Euphorbia Journal (1985) volume 3 “Flowering parts of the Caput Medusae group, Part 2”, page 90. Graham Williamson (2011b) is the only author mentioning it in 14 volumes of Euphorbia World.

In the species list of succulent plant hunter John Lavranos, we find two localities for Euphorbia tuberculatoides and a third with a question mark added. One of these is just south of Vredendal. On a trip I made in 2017 I was passing by, so I decided to check out this locality, where I found the plants easily. My first impression was that these plants indeed were something different from Euphorbia tuberculata. They were – at most – half the size with shorter, rigid branches, covered with more or less straight peduncles (Fig. 28). Also they did not show the behaviour of the branches becoming erect when stressed by drought. Unfortunately I saw no flowering or fruiting plants. Their smaller size matches the description of Euphorbia tuberculatoides, but the type-locality south of Hopefield is over 150 km to the south and the long slender branches of its type do not match the thicker rigid lateral branches covered with woody persistent peduncles of the plants I found here. Although I was intrigued how different these plants were, I was of the opinion they must be within the range of variation of Euphorbia tuberculata.

It was much later when I realized that several other populations, all occurring in the northern range of the natural distribution area of Euphorbia tuberculata shared the same characteristic features, namely: smaller size, thicker and rigid lateral branches covered with persistent peduncles. The populations were Moedverloor (north of Holgat River) (Fig. 29), north of Koekenaap (Fig. 30) and north-east of Vanrhijnsdorp (Fig. 31). At the latter locality plants had thinner and less rigid branches. When visiting these populations, some more than once, I never observed flowering or fruiting plants. These localities are all found near or in the Southern Knersvlakte, which has a more arid climate than the Clanwilliam – Lambert’s Bay area. Still the differences in the habit of the plants are quite striking. It is of interest whether the flowers and fruits show constant differences or should be identified as Euphorbia tuberculata.

Conclusion: Further research is needed to evaluate the taxonomic status of these populations.

Euphorbia marlothiana

Euphorbia marlothiana was described by N. E. Brown (1915) in The Flora Capensis. The species is characterized by a rootstock or main stem completely buried in the ground. This can be seen in the picture by Ernst van Jaarsveld in The Euphorbia Journal (1996). In most specimens this main stem is only slightly thicker than the lateral branches, which can also be club-shaped at their tips and forming secondary branches. Euphorbia marlothiana grows in the sandy coast-veld. Sometimes only the tips of branches can be seen (Fig. 32). But sometimes also dense clusters of branches, freely re-branching, can be found (Fig. 33). The peduncles are described as 8-50 mm long, ultimately withering and often persistent, but not becoming hard or woody (Fig. 34).

Euphorbia marlothiana was originally described from material found by Dr. Marloth (Marloth 5733) in the heart of the Cape Flats on sandhills near Neu Eisleben. I cannot find out where Neu Eisleben was and whether the type locality still exists. The Cape flats are the flats bordering False Bay, to the south-east of Cape Town and now a densely populated area. It is interesting to note that N. E. Brown (1915) found it worthwhile mentioning the place was about 10 miles distance from the nearest railway station. Also in his comments with the description of Euphorbia marlothiana N.E.Br. he called the new plant Euphorbia marlothii.

I saw Euphorbia marlothiana at several spots in or nearby the Koeberg Nature Reserve. It is not rare here and can be found under or near bushes and low shrubs, growing in deep sandy soil. This corresponds well with the distribution area given by White, Dyer & Sloane (1941), as sparsely distributed mostly on the sand dunes near Cape Town and the Cape Peninsula and to the north of Cape Town.

Euphorbia marlothiana has been reported as growing on the Cape Peninsula a very short distance from Euphorbia caput-medusae. Yet both species maintain their own characteristics. This seems proof to me there is a specific genetic barrier between the two species and they are not the same thing.

Taxonomical status.

Euphorbia marlothiana N.E.Br.: Fl. Cap. (Harvey) 5(2.2): 331 (1915).

Type: South Africa, Cape, near Neu Eisleben, Marloth 5733.

Description of Euphorbia marlothiana taken from White, Dyer & Sloane (1941).

Plant: a dwarf succulent, spineless but with persistent remains of the peduncles; main stem a continuation of the thickened main root forming a clavate or elongated-obconic body whole buried in the ground, often subglobosely thickened at the apex, from which arise several erect or ascending branches; branches 7.5 to 40 cm. long, when young 6 to 10 mm. thick, tuberculate, with age becoming also buried in the ground, sometimes clavate like the main body, up to 2.5 cm. (or more?) thick, and in turn producing slender branches at their apex; tubercles rhomboid or oblong, flattish and only 1 to 1.5 mm. prominent.

Leaves: soon deciduous, 2 to 6 mm. long, oblong or linear, spreading, channelled, acute, with recurved tips, fleshy, glabrous.

Inflorescence: cyathia solitary, produced 1 to several together at or near the tips of the branches, pedunculated; peduncles 0.8 to 5 cm. long, erect, glabrous, ultimately withering and often persisting, but not becoming hard or woody; bracts surrounding the involucre, soon deciduous; involucre broadly and rather shallowly bowl-shaped, 1.2 to 1.4 cm. in diameter, with 5 glands and 5 large erect, subquadrate, toothed, purplish lobes 2.5 mm. long and broad, glabrous; glands separate, spreading, divided to slightly below the middle into 2 to 6 linear white processes (becoming reddish with age) dilated and slightly branched at their tips, with the undivided part broadly wedge-shaped, without a lip or turned-up margin at the base, 2 to 2.5 mm. long and about the same breadth across the top, with revolute sides, green.

Pistillate flower: ovary sessile, included in the involucre, subglobose, pubescent ; styles united into a column about 3 mm. long at the base, free above, the free portion short, dilated and bifid at the tips;

Capsule: sessile, obtusely 3-lobed.

Type locality: Cape Prov.: Cape Distr.: near Neu Eisleben.

Distribution: Cape Distr.: also at Milnerton, north of Cape Town; Wynberg Distr.: near Strandfontein.

Euphorbia muirii

Euphorbia muirii was also described in The Flora Capensis (1915, page 331) by N. E. Brown, who discussed it in the notes added to the description of Euphorbia marlothiana. He compares Euphorbia marlothiana with Euphorbia muirii as evidently having the same general habit, but differing distinctly in having more flowers on a branch, peduncles withering in a different manner, larger involucres and the glands having their undivided part twice as broad as long, the inner margin not turned up. This last feature of Euphorbia muirii having a turned-up inner margin of the gland is quite remarkable, as this feature is not known from any other species discussed in this article, or any medusoïd species of Euphorbia at all. In fact such a turned-up inner margin is the characteristic feature of species of the section Dactylanthes such as Euphorbia globosa and E. tridentata.

1. E. Brown based his new species on three collections, namely: Pearson 2261, collected at Sand Berg, some 10 km south-west of Robertson; Muir s.n. and Muir 174, from Still Bay. Regarding these two last collections N. E. Brown adds that they probably also belong here, but were without flowers or fruit. Taking this last remark into account it is not surprising that White, Dyer & Sloane (1941) cited Sand Berg as the type-locality.

How logical the above may seem, N. E. Brown actually wrote “Type” on the herbarium sheet of Muir s.n., not on the herbarium sheet of Pearson 2261. Selecting Muir s.n. as the type of Euphorbia muirii seems to be a contradiction in itself, as he wrote in his notes ‘probably also belongs here’. It gets even more complicated as Bruyns (2012) designates Muir 174 from Platbos, Still Bay as the lectotype. The herbarium sheet of Muir 174 is stored in Pretoria and I have not seen it, but the sheet of Muir s.n. and Pearson 2261 are stored in Kew and can be viewed on the website of the Royal Botanic Garden.

Together with Alma Möller, Rolf Becker and Jaap Keijzer, I found plants just west of Gouritsmond, over 350 km east of Cape Town, very close to the beach, growing in the white coastal sands of the Indian Ocean (Fig. 35), which I thought at that time to be my first record for Euphorbia muirii in habitat. In general the habit was very similar to Euphorbia marlothiana, which I had seen several times before near Mamre. The main differing features were that the peduncles were shorter, thicker, straight and hardly as persistent as in E. marlothiana (Fig. 36). These peduncles had well developed bracts and they were tubercled. Some plants had an odd flower (Fig. 37) and more differences were to be noted: the outer involucre and glands were pubescent and the glands were shortly but distinctly stalked.

Comparing this flower with the original description of Euphorbia muirii, one can definitively conclude that these plants from west of Gouritsmond differ from the plant N. E. Brown (1915) described as Euphorbia muirii. Mainly because in the description of the latter the turned-up inner marging of the glands with its undivided part twice as broad as long. However it is very probable that the plants collected by Dr. Muir at Still Bay are similar to the plants we found west of Gouritsmond, the more so because N. E. Brown remarked he did not see flowers or fruit of the Muir collections. Also it is obvious the description of the flowers with the turned-up inner margin of the gland are taken from the Sand Berg collection, Pearson 2261. Despite this N. E. Brown made Muir s.n. the type specimen.

As for now several questions need to be answered.

• Are the Muir collections similar to the plants we found west of Gouritsmond? If they are similar these plants should be referred to as Euphorbia muirii.
• If they are similar, the question is: Are they different from Euphorbia marlothiana? If this is the case Euphorbia muirii needs a new description.
• Is there a medusoïd species growing at Sand Berg near Robertson, with the habit of Euphorbia marlothiana and flowers with glands having a turned-up the inner margin of the gland with an undivided part twice as broad as long? If this is the case it needs to be described as a new species.

As long as these questions remain unanswered, it is best to maintain Euphorbia muirii as an imperfectly known species.

Taxonomical status:

Euphorbia muirii N.E.Br.: Fl. Cap. 5(2.2): 331 (1915).

Type: Muir s.n., Still Bay, Albertinia, Riversdale District.

Description of Euphorbia muirii taken from White, Dyer & Sloane (1941) and underlined where revised.

Plant: a dwarf succulent, spineless but with some persistent remains of the peduncles; main stem a continuation of the main root, wholly buried in the ground; branches produced below the ground level, up to 18 cm. long, 0.6 to 1.5 cm. thick, increasing in thickness upwards, rebranching above, tuberculate, glabrous; secondary branches more or less whorled, 0.5 to 3.5 cm. long; tubercles rhomboid, 0.5 to 1.3 cm. long, 1.2 mm. prominent, tipped with a leaf scar.

Leaves: erect, 0.5 to 2 cm. long, 1 mm. broad, linear, acute, glabrous.

Inflorescence: cyathia solitary, produced near the tips of the branches on peduncles arising from the axils of the tubercles; peduncles 0.5 to 2 cm. long, deeply ribbed, glabrous, bearing 4 to 6 bracts, sometimes persisting; bracts 3 to 4 mm. long, oblong, acuminate, concave, crenate, shortly ciliate, glabrous outside, thinly pubescent within; involucre cup-shaped, 1.2 to 1.5 cm. in diameter, with 5 glands and 5 large, transversely elliptic, toothed lobes, thinly pubescent outside and in front of the glands and on the lobes within, almost entirely stained with bright red; glands not contiguous, 3 to 4 mm. in diameter, broadly cuneate, palmately divided to about half-way down into 4 to 6 linear yellowish-white processes, with each process dilated and irregularly toothed at the apex, with the undivided part entirely glandular and yellowish-green and turned up at the inner margin to form a small lip.

Pistillate flower: ovary sessile, glabrous; styles 3 to 4 mm. long, united into a column nearly to the apex, with bifid tips.

Capsule: sessile, obtusely 3-lobed, 6 mm. long, 1 cm. in diameter, glabrous.

Type locality: Cape Prov.: Riversdale Distr.: Albertinia, Still Bay.

Distribution: Also in Mossel Bay Distr.: Hartenbosstrand.

Uncertain identifications related to E. muirii

In The Euphorbia Journal, volume 2, page 69 (Anonymus, 1984) we also find a picture of a flower attributed to Euphorbia muirii. Recently Itay Yanco from Israël sent me a picture of the very same cyathium (Fig. 38). Both pictures obviously do not show the plant N. E. Brown (1915) described as Euphorbia muirii, as the characteristic features of the undivided part of the gland is not twice as broad as long and there is no turned-up lip at the base of the gland. I don’t know what species is involved here or where it originates from.

In this context, another species described by Brown (1915) must be mentioned here, namely Euphorbia bergeri N.E.Br. At the time of its description it was unknown in nature and regarded as a hybrid. I have grown plants also of unknown origin, labelled as Euphorbia bergeri, for many years in my collection and they show a very similar habit as both Euphorbia marlothiana and Euphorbia muirii. However, Brown states E. bergeri to be very similar in appearance to Euphorbia caput-medusae. The best explanation that comes to mind would be that Brown compared it to a cutting of a lateral branch of Euphorbia caput-medsuae, which also has no thick main-stem. It might very well be a hybrid and the cyathia (Fig. 39) remind me of those of Euphorbia fimbriata Scop., but the large involucre bracts are a striking and unique feature for a medusoïd species. Again a picture of Euphorbia bergeri is found in The Euphorbia Journal, volume 3, page 89 (Anonymus, 1985), which is a different plant and could very well be Euphorbia davyi Pax ex N.E.Br. in my opinion.

Euphorbia bolusii

Euphorbia bolusii is another imperfectly known species, also described by N. E. Brown in the Flora Capensis (1915), and only known from a few dried branches collected by Dr. Harry Bolus around 1900. Euphorbia bolusii was originally found near Middelburg, approximately 100 km east of Pretoria in Mpumalanga. This locality was very much doubted by White, Dyer & Sloane (1941), because “it is possible that there has been an error in making the record, especially as a diligent search in the neighbourhood has revealed no trace of the plant” (page 374). So White, Dyer and Sloane (1941) referred to the type locality as “? … near Middelburg”. Searching an area diligently without success is hardly proof that the given type-locality is a mistake. Everyone who has ever searched for these little and inconspicuous plants knows how deceptive they can be.

1. E. Brown (1915) compared this species to Euphorbia tuberculata stating: “habit probably something like that of E. tuberculata, Jacq.” (pages 333-334).

White, Dyer & Sloane (1941) compare Euphorbia bolusii to Euphorbia tuberculata and Euphorbia maleolens E.Phillips, but conclude they are different species because the structure and colour of the involucre glands differ. They state that the glands in fact are virtually identical to the ones found in Euphorbia tuberculata and its allies from the west coast region. Euphorbia bolusii again is mentioned by White, Dyer & Sloane in the caption of Fig. 376, discussing a plant found 48 kilometres west of Steinkopf, which is clearly Euphorbia ramiglans N. E. Br. var. confluens (Nel) van Veldhuisen. As discussed under Euphorbia ramiglans N. E. Br. the branching of the processes on the glands is different from Euphorbia tuberculata Jacq. However White, Dyer & Sloane retain Euphorbia bolusii N. E. Br. as a distinct, imperfectly known species.

Bruyns (2006) concludes that Euphorbia bolusii is not distinct from Euphorbia caput-medusae. This is argumented by the fact the locality given is considered to be an error, whereas White, Dyer & Sloane (1941) state it is possibly an error. Although no new information has become available since their publication, Bruyns (2006) comes to a different conclusion.

In the context of this article it is worth mentioning that the few known branches of Euphorbia bolusii collected are only 5-6 cm long. S

As Euphorbia tuberculata Jacq. and Euphorbia ramiglans N. E. Br. are distinct species, and it is not certain whether Middelburg as type locality is a mistake, then if it is a mistake and Euphorbia bolusii is in fact Euphorbia tuberculata or Euphorbia ramiglans, the conclusion of White, Dyer & Sloane should be maintained and Euphorbia bolusii considered as an imperfectly known species.

Near Middelburg I found Euphorbia davyi Pax ex N.E.Br., another medusoïd species N. E. Brown described in the Flora Capensis (1915). This is also a small sized medusoïd species of Euphorbia growing in the same Euphorbia bolusii, when dealing with this species or vice versa. He evidently decided both were valid species.

Uncertain identification related to E. bolusii

1. E. Brown (1915) made a detailed description of the glands in his publication of Euphorbia bolusii. In this he describes them as: “broadly cuneate-palmatifid” (i.e. wedge-shaped and lobed like fingers from a palm) and later: “something like a reindeer’s horn” (Brown, 1915, page 332).

In November 2006 I visited the keen collector of Lithops Josie Brandt in Griekwastad. In her collection she had a few Euphorbia specimens. One of these was a small medusoïd plant, originally collected in the vicinity of Kimberley (Figs 40 and 41). This little plant was flowering at the time and was unlike anything I know. With quite a bit of imagination the glands resemble a reindeer’s horn. Even though Kimberley is some 500 km distance from Middelburg, I cannot help wondering whether this plant might be Euphorbia bolusii, even despite the fact N. E. Brown (1915) described the processes of the glands as bifid, which can’t be seen on Fig. 41. Still, it is an example of small, insignificant medusoïd species being discovered and we are far from having the complete picture.

In accepting this fact there is only one conclusion: Euphorbia bolusii should be maintained as a species, although imperfectly known.

Taxonomical status.

Euphorbia bolusii N. E. Br.: Fl. Cap. (Harvey) 5(2.2): 333 (1915).

Type South Africa, Transvaal, near Middelburg, H. Bolus 9767.

Description of Euphorbia bolusii taken from White, Dyer & Sloane (1941).

Plant: probably a dwarf succulent, spineless but with persistent ascending remains of the peduncles, possibly resembling E. tuberculata Jacq. in habit, but only 3 dried branches have been preserved, which resemble those of that species, but are apparently much shorter, 5 to 6 cm. long, 1 to 1.3 cm. thick, covered with elongated subrhomboid tubercles 6 to 8 mm. long, 3 mm. broad and 3 to 4 mm. prominent, compressed-conic, slightly recurved.

Leaves: not described, probably soon deciduous.

Inflorescence: cyathia solitary, produced on peduncles arising from the axils of the tubercles at the tips of the branches; peduncles erect or ascending, 1.2 to 2.5 cm. long, glabrous, bearing a whorl of 4 bracts at the apex under the involucre; bracts elliptic, obtuse, concave, glabrous, not ciliate, probably no more than 4 mm. long, deciduous; involucre broadly cup-shaped or obconic, 9 mm. in diameter, glabrous or nearly so outside and within, with 5 glands and 5 subquadrate lobes, toothed at their truncate tips; glands subcontiguous, broadly cuneate-palmatifid, 3 to 3.5 mm. long and about 5 mm. across the tips, divided to more than half-way down into 4 to 6 apparently white segments 1.5 mm. long, which are bifid to the middle with their flat lobes diverging, recurved and toothed something like a reindeer’s horn, and the gland occupying the whole of the undivided part, not pitted.

Pistillate flower: ovary sessile and included in the involucre, glabrous; styles united to the apex into a slender column 5 mm. long, with minte tips, glabrous.

Type locality: ?Transvaal: Middelburg Distr.: near Middelburg.

Distribution: Not further known.

Some final remarks

Graham Williamson (2011a, 2011b) paid a lot of attention to the climatic differences of the natural habitats at the different localities of the species discussed. As his title says they range from the Cape of Storms to the arid wind-blasted sands of the Namib desert. And indeed the climate varies from the arid desert of The Richtersveld, with an average rainfall at Alexander Bay of 20 mm per year, to The Cape Peninsula with an average rainfall of 788 mm per year.

The question arises how useful it is to accept such different plants as for instance Euphorbia marlothiana and Euphorbia tuberculata (which are growing only a short distance from one another) as one species. The argument that no clear line of characteristic morphological features can be drawn between any of them is not the case. When someone tells me he or she has seen Euphorbia caput-medusae in nature, it could well be the Alexander Bay miniature or the plant of more than 1 m diameter from the Cape Peninsula. Also if someone were to ask me how to grow Euphorbia caput-medusae, the same advice for every plant could result in a shrivelling plant originating from the Cape or a rotting plant originating from Alexander Bay. Of course these are by no means scientific arguments, but it is also far from effective communication to abandon the nomenclatural distinction between such different plants.

Also there are reasons for the sake of nature conservation not to accept too broad a species concept. Most of the taxa discussed here are not rare in nature and happily still can be found growing at many localities. But if one of them only grows in few numbers of individuals in just a small area, as often is the case in species of Euphorbia, how do we protect such a population if it is included in a broad-range “super-species”? One could argue it is just another Euphorbia caput-medusae with no specific importance for the protection of the entire species. If, however, a small population of plants is well defined as a separate taxon, it would be more urgent and worthwhile to protect such plants.

Conclusions

– In this article I support the view that Euphorbia caput-medusae and Euphorbia tuberculata are both good species. Euphorbia tuberculata is the linking species between Euphorbia caput-medusae and a group of other medusoïd species, that have been sunk into synonymy under Euphorbia caput-medusae. Their positions need to be revised.

– Euphorbia tuberculata var. macowanii (N.E.Br.) A.C.White, R.A.Dyer & B.Sloane has not been recorded from its type-locality for over 80 years and differing features are most likely contributing to the variability of Euphorbia tuberculata. It is reduced to synonymy under Euphorbia tuberculata

– Euphorbia ramiglans N.E.Br. is distinguished as a distinct species by its cyathia with white filiform processes, being much branched at their tips.

– There is little doubt anymore about the identity of Euphorbia confluens Nel. The differing features are however not always present in comparison with Euphorbia ramiglans. More so, the flowers of both are similar, so Euphorbia confluens Nel is reduced to a variety of Euphorbia ramiglans.

– It is probable that Euphorbia tuberculatoides is a distinct species, yet closely related to Euphorbia tuberculata. But as long as I do not know the plant from its type-locality this is difficult for me to prove. At best it can be regarded as an imperfectly known taxon.

– The most northern populations, mostly regarded as Euphorbia tuberculata, bordering the arid Knersvlakte, are found differing in size and with more rigid branches with short, persistent peduncles. These populations deserve further research to decide upon their status of being a variation within the species Euphorbia tuberculata, a variety of this species, or perhaps a distinct species.

– Euphorbia marlothiana N.E.Br. has to be regarded as a valid species because of the different habit, which is maintained although it grows within short range of Euphorbia caput-medusae.

– Plants found along the coast between Cape Town and Mossel Bay might be identical to the type of Euphorbia muirii, collected by Dr. Muir at Still Bay, Albertinia. If this is the case, this is not the plant N. E. Brown (1915) described as Euphorbia muirii in the Flora Capensis as it does not fit the description. Until plants fitting this description are found again, hopefully at or near the type locality, it is best to regard them as an imperfectly known taxon at species rank. The plants found growing near Gouritsmond are similar to Euphorbia marlothiana N.E.Br., but different in some aspects. Further research is necessary to decide upon their status.

– Euphorbia bolusii N.E.Br. from Mpumalanga is an imperfectly know species that appears to deserve species rank.

Acknowledgement

The Herbarium at the University of Limpopo is thanked for information used from The Leach Archive, which has been scanned by funding of the PBI project.

References

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Brown, N. E. (1915): Euphorbia. In W. T. Thiselton-Dyer (ed.): Flora Capensis, Vol. 5, section 2, part 2. Ashford, L. Reeve & Co.

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