Euphorbia subgenus Euphorbia section triacanthium
Jacobsen.
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Of all the species of Euphorbia one of the most sought after by collectors
is Euphorbia schizacantha. Beauty is in the eye of the beholder, but
I think this is rightfully so.
As a species E. schizacantha is easily recognizable, for the fusion
of the two upper spines is not complete. The tip of this fused main
spine is split into a little fork. This little fork is pointing away
from the plant, because the two tips make a narrow angle. This feature
makes it readily distinguishable from E. glochidiata, which also has
a split main spine, but with the tips at a right angle with the main
spine.
Together with E. kalisana and E. triaculeata they represent the biggest
plants in this group. In the Euphorbia Journal (1984) E. schizacantha
is reported as having a maximum size of about 1.2 metres in height,
Pax (1904) reports 1 metre, but Susan Carter (1988) talks about a maximum
height of 0.6 metre. M. Gilbert, in his Flora of Ethiopia and Eritrea
gives a measurement of 30-45 centimetres, with lateral branches of up
to 40 cm. Despite these differences, in all cases it is the height of
the main stem with the side branches drooping downwards to soil level,
which is different from the other species, E. kalisana and E. triaculeata,
which have a very much depressed main stem with side branches reaching
more or less for the sky. The size of the main stem makes E. schizacantha
not the tallest but nevertheless the most impressive species in this
group.
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Euphorbia schizacantha has a very wide natural distribution area, which
stretches out from Kenya, Somalia and Ethiopia. In the drier areas in
the North it remains smaller and shows a more compact growth. Also the
colour of the cyathia is variable, from yellow to dark blood-red. Particularly
this latter is a very beautiful form, because also the plant body is
covered with red, green and light green patterns in a very showy way.
In quite a few accounts of journeys to the distribution area of this
species, Euphorbia schizacantha is mentioned. I assume this is not only
because it is a beautiful and impressive species, but also because it
is fairly widespread and common in nature. This also explains it is
an 'old' species and already described in 1894 by Pax. How ever common
it may be in nature, it is rarely encountered in cultivation where it
is very hard to please, and which strangely enough adds to its desirability.
Even very skilled growers of Euphorbias are driven mad by its whims.
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A very very light and warm place is highly appreciated, but full sun
all day long stops the growth, which is not resumed very easily and
will lead to the loss of the plant. In the short growing season it likes
ample water and in this period it grows rather quickly, though not for
a long time. When not in growth, Euphorbia schizacantha is killed right
away, when given too much (cold) water. Sowing seed of this self fertile
species is the surest method of growing typical offspring and seedlings
are in the first season relatively easy to grow. Also the cutting-two-times
method works for this species in order to get a typical plant with the
thick main stem, however this is sometimes denied in literature.
Through its special beauty and tricky cultivation Euphorbia schizacantha
appeals to the imagination of many Euphorbia growers.
Euphorbia monacantha Pax.
The second Euphorbia described by Pax is Euphorbia monacantha. The description
from 'Engler's Botanisches Jahrbuch für Systematik' of 1904 is rather
short and without a picture. Sadly enough this was the case with numerous
newly described species at that time and this has led to many misidentified
plants among the lesser known species. The name Euphorbia monacantha is
of all the species names in this group one of the most frequently used
on labels, however it is not in cultivation at all. Also the meaning of
its name is wrong as well, being the 'one-spined Euphorbia'. In fact there
are of course one upper main spine above and two little spines below on
the spine shield. The latter two are normally designated prickles. All
this confusion is caused mainly by the fact that many new undescribed
species from this group of plants found their way to collections in the
seventies and eighties under the name E. (spec. aff.) monacantha.Euphorbia monacantha was found in 1901 by Dr. Ellenbeck at Gorobube on stony flats at 1700 metres above sea level. Gorobube was situated in Arussi County, Gallaland. Of these names today not many references can be found, but nowadays this region is called Bale Province. As far as known (Dr. M. Gilbert, pers. com.) Euphorbia monacantha has only once been recollected and apparently it only grows in a very small area.
In the short description of this species by Pax it is described as: 10 – 20 Centimetres high, with yellow cyathia; the single branches less than 4 centimetres long, spines 4 centimetres long and more. There is no mention of a main stem or how thick it can become. I can imagine thick compact plants with very short lateral branches, covered with fierce spines. What a thrill that would be for Euphorbia lovers to cultivate such plants; it would win the popularity contest over E. schizacantha.
I have never seen anything like this alive, there is however a picture in the 'Euphorbia Journal' (1987) of a plant coming close to this. In the photo gallery is a plant labelled as Euphorbia species nova Gilbert (Kew 228-83-02608). A compact, densely branched and fiercely spined plant found by Mike Gilbert in Ethiopia. He assumes however these plants belong to E. actinoclada and so Euphorbia monacantha remains unknown.
N. E. Brown later places another species described by Pax, Euphorbia xylacantha, as synonymous under E. monacantha. Susan Carter (1992) reinstated E. xylacantha as an independent species with an extended description.
For the time being Euphorbia monacantha will take a high place on my wish list and plants labelled as E. monacantha need closer inspection.
