Euphorbia awashensis M. Gilbert. Part 3
Rikus van Veldhuisen
In 1992 as much as four species belonging to this group have been described, of which only Euphorbia awashensis has not by Susan Carter but by Mike Gilbert. This species is only known to grow on one single locality in the Awash National Park in Ethiopia. We are dealing here with a small shrublet, only 30 centimeters high, weakly spined and the lateral branches becoming as thick as 0,7 centimeter. In contradiction to the other species Euphorbia awashensis is growing is grasslands. The main stem is retracted below soillevel, which is a keen adaptation in order to protect it against the occurring fires.
- Gilbert (1992) adds to his first publication of this species the fact that it has been collected only twice. One time by somebody named Raymonde Bonneville, during an archeological trip, being unaware of the whereabouts of the collected material. The other collection was made by himself of a living plant in 1969. This plant was cultivated for some years by him in Addis Abeba, before he gave some cuttings to the late Frank Horwood in the United States. Frank Horwood was known to be a very skilled grower of Euphorbias and was also successful in multiplying this species. Therefor Mike Gilbert assumes there is still living material in collections.
Fact is that Specks sold plants as Euphorbia monacantha, salesnumber ES2071, originating from the United States. They attract attention by her elongated growth and the thin weakly spined branches. In order to keep this thing growing, it needs ample watering. Another costum of this plant is its vulnerability of branches getting infected and dying back. As with other Euphorbias this this phenomenom normally causing the loss of the plant, in this species mostly the plant survives. This can be clearly seen on the plant pictured in figure 36 and this feature makes it not one of the most fancy to grow.
However I am not 100 % sure about the identity of ES2071, my best guess would be it is Euphorbia awashensis indeed, because of the way it behaves in cultivation and its habit do match the features mentioned by M. Gilbert in his original description. This issue could be closed when I would be able to grow seedlings one time which do show the retracted main stem below soillevel.
Euphorbia erigavensis S. Carter.
The three other species described by Susan Carter have been published in the Nordic Journal of Botany. This publication is supplied with drawings of the plant, however there are no photos added as well. For the average hobbyist a photo is much less trickier to put a name to a plant than a drawing. Once seen a certain plant, even on a picture, makes one much more confident the identification is correct.
Euphorbia erigavensis is native in a very small area in the neighbourhood of Erigavo, Somalia. This plant is characterized by its small size of only 30 centimeters in height and despite its size it is still a very robust plant. The main stem elevates hardly above soillevel and the few lateral branches, which in turn also sparingly rebranch and are as thick as 2,5 centimeter, are bend upwards like a candelabre and supplied with 3 centimeter long, robust spines. These lateral branches are remarkeable sturdy and give this species its robust appearance.
I know of only one picture of this plant ever to have been published in literature, which is a habitat picture in the Euphorbia Journal (1994). For many years I grow this species in my glasshouse under the name Euphorbia monacantha ‘Riley’. I assume ‘Riley’ was once the collector of these plants. Anyway, these plants make a perfect match with its description and picture, so I am quite certain it really is this species I am growing. Another characteristic feature is the yellowbrown bodycolour Euphorbia erigavensis has in cultivation, which is also evident on the habitat picture. In cultivation it does not present to much difficultities for the grower and it is a reliable flowerer as well. The two-step-cutting method failed to work for this species, at least for me it did. Lateral branches taken as a cutting do flower even more profusely, which is quite handy when seeds are needed.
It is well known of course that the sowing of succulent plants can yoeld great satisfaction. When you are successful, you are not only rewarded by a surplus of spare plants, but also the plantlover can make observations a scientist rarely does. Sowing is a rather time consuming occupation and time is a thing a scientist not always has as much as a hobbyist. So can one observe that the pattern are colouration in seedlings quite often is much more pronounced than on adult plants. In this manner the tiny seedlings are better hidden for planteaters and so the chance of becoming an adult is bigger. Another remarkeable feature one can observe on seedlings of this related group of plants at first do have four spines at each spineshield and later the two upper spines are fused in one. This can be seen as an evidence of the close relationship of this group of plants to the four spined ones. This phenomenon can be clearly seen on picture 29 representing a small seedling of Euphorbia erigavensis.
Euphorbia margaretae S. Carter.
Only a little time ago I knew of only one photo in literature in again the Euphorbia Journal (1987). On this picture is a cultivated plant and some short notes are added. It is very annoying that in this notes is mentioned its easy cultivation and the abillity of making heads as sideshoots. The multiplication of this species must be more difficult than stated or was severly neglected, because I have never seen a plant or being offered for sale in a list or anywhere. This is a great pity, because on the mentioned picture is a extremely handsome plant.
In nature Euphorbia margaretae is found only once by Margaret Johnson, also as the forgoing species in the neighbourhood of Erigavo, Somalia. It becomes a densely branched shrublet of 25 centimeter high en measuring 75 centimeter in diameter. Quite remarkeable S. Carter (1992) writes that this species does lacks the characteristic main stem. This could well be a misunderstanding, for she could have made the description of this species on base of sterile cuttings only. Besides this is in the Euphorbia Journal (1987) said it makes heads as sideshoots on branches taken as a cutting.
The most characteristic feature of this species is in my opinion that the fusion of the two upper spines is not complete, as in the case of Euphorbia schizacantha. The before mentioned picture shows a densely branched plant with nice black spines in the new growth and is having a blue haze over the green plantparts. It is hoped for that this species becomes available to the Euphorbia-enthousiasts, because it seems a valuable addition to every collection. Remarkeable is also that there is no sign of rebranching sidearms on the plant.
Recently I received a habitat picture of Euphorbia margaretae from Giuseppe Orlando, our I.E.S.-representative of Spain. He has taken this picture during a very adventorious trip to Somalia, north of Erigavo. This picture clearly shows the habit of thin and densely rebranching sidearms.
Euphorbia myrioclada S. Carter.
This species is somewhat a puzzle to me. Never came across any picture of this species in literature and the only representation is the drawing accompanying its first description. The few times I did meet with plants under this name in cultivation, however they were identical to the ones I take to be E. awashensis. Susan Carter (1992) describes a plant with a 5 centimeter high and 2 centimeter thick main stem, which branches into a dense shrublet of 30 centimeter high and 50 centimeter across. These lateral branches are up to 8 millimeter thick and do rebranch freely. The orangeyellow cyathia does not make it stand apart in this group of species. Only three collections in nature have been reported of this species in the Woqooyi Galbeed area, Somalia, of which the first was already in 1944 made by P. R. O. Bally.
Susan Carter compares this new species with Euphorbia triaculeata from Djibouti and Eritrea and concludes that the last species grows bigger and is more robust in all parts. The situation is more complex than mentioned, not only because the most recent described Euphorbia godana originates from Djibouti, but also the under Euphorbia triaculeata, which for sure is not it, mentioned form AJB D3 comes also from Djibouti. The reason why Susan Carter descrbes Euphorbia myrioclada as a species, without taking other forms of resembling plants of other areas into account, I can only guess. Furthermore as long as I don’t know the real Euphorbia myrioclada I cannot comment on this subject.
Euphorbia species nova Mrs. Ash.
Now that all described species* in this group have passed the revue I want to put some forms under attention of the reader, which are running around in collections and which I cannot put under a specific species. The International Succulent Institute has distributed under her number ISI 1201 Euphorbia species nova Mrs. Ash under succulentcollectors. This is particularly interesting for it is one the few plants in this group spread around with good localitydata, for a certain Mrs. Ash collected this plant between Neghili and Filtu in the south of Ethiopia. Remarkeable as well is the fact the I.S.I. sold this plant both as rooted cutting for 5 Dollar or as rooted head for 9,5 Dollar.
A characteristic feature are the big yellow, with a green haze, cyathia and plants are somewhat more robust in all aspects than Euphorbia actinoclada. The feature that in a very sunny cultivation the marbled stems turn dark green and purple adds to the charm of these plants, The before mentioned locality is within the natural distribution area of Euphorbia actinoclada. In the very variable species concept, as is applied today, Euphorbia species nova Mrs. Ash, could be seen as another striking form of Euphorbia actinoclada. It is in quite some details very similar to plants of the ‘Bulthuis’-clone of Euphorbia actinoclada. When someday somebody splits Euphorbia actinoclada into several distinct species this Euphorbia species nova Mrs. Ash might be one of them.
Euphorbia species 632.
I grow plants in my collection, with my clonenumber 632, which obviously belong to our group, but are not even close to one of the mentioned species. This plant attracts attention, because cuttings taken never form the central depressed main stem and rebranch freely, so that a shrub is formed. One time there was a plant in cultivation in the collection of Jaap Keijzer measuring more than one meter in height. Young spines are black and the mainspine is relatively short and quite thick. The gleaucous plantbody is quite atractive for it is covered with a blueish haze and it flowers also freely with orangeyellow cyathia. Unfortunately it never has set seed so far, so it is not certain seedlings will form the thick mainstem or not.
Also I have no further information about the origin or the natural habitat of this plant, so her identity remains a mystery. Perhaps some reader recognizes this beautiful plant and can enlighten the ignorant writer.
The writing about this beautiful and remarkeable group of related Euphorbias originating from most of the times difficult to access areas does not end here. At least three new species have described recently and an additional paper is in preparation in order to complete the total of species belonging in this group. They form, also for the specialized collector, a challenge to grow and to multiply them. All things stated are through the eyes of a hobbyist and to my sadness I must admit that not one of these species have ever been observed my me in their natural environment. So I want to emphasize that there is no scientific base for remarks made.
Furthermore a word of special thank you must be made to Mike Gilbert, Jaap Keijzer and Pjotr Lawant for their support and guidance. I only hope that these delightfull species might be become more widely appreciated, both to hobbyists and scientists. I am convinced many spectacular new finds will be made in nature, which will lead to many new descriptions of species.
*This is not true any more, since three species have been described very recently. In an appendix these three species will be presented to our readers.
- Bally, P. R. O., & Carter, S., Miscellaneous Notes on the Flora of Tropical East Africa, including Descriptions of New Taxa, 33 – 36, Candollea 21, blz. 365 – 373, 1967.
- Carter, S., New Succulent Spiny Euphorbias from East Africa, Hooker’s Icones Plantarum, Vol. 39, Part 3, 1982.
- Carter, S., New Taxa in Euphorbia subgen. Euphorbia from Eastern Tropical Africa, Kew Bulletin Vol. 42(2), 1986.
- Carter, S., Problems of Distinction among Succulent Euphorbia Species from Eastern Tropical Africa, Botanical Journal of the Linnean Society, 94, blz. 67 – 78, 1987.
- Carter, S., -Smith, A. R., Flora of Tropical East Africa, Euphorbiaceae (Part 2), 1988.
- Carter, S., Euphorbia Pictures by P. R. O. Bally, The Euphorbia Journal, Volume 5, page 76 – 82, 1988.
- Carter, S., New Pair-spined Species of Euphorbia (Euphorbiaceae) from Somalia, Nordic Journal of Botany, 12, blz. 403 – 422, 1992.
- Carter, S., Some Unresolved Problems among Somali Euphorbia Species, Collectanea Botanica (Barcelona) 21, blz. 57 – 66, 1992.
- Chiovenda, Emilio, Euphorbiaceae, Flora Somala (I), Roma, 1929.
- Gilbert, M. G., Notes on Euphorbia subgenus Euphorbia in Ethiopia, Collectanea Botanica (Barcelona) 21, blz. 67 – 77, 1992.
- Gilbert, M. G., Flora of Ethiopia and Eritrea, Vol. 2, Part 2, Uppsala, Sweden, 1995.
- Jacobsen, Hermann, Lexicon of Succulent Plants, 1977.
- Pax, F., Monographische übersicht über die Afrikanische Arten aus der Sektion Diacanthium der Gattung Euphorbia, Engler’s Bot. 34, 61 – 85, 1904.
- Rauh, Werner, Little Known Succulents from Southern Arabia, Cactus and Succulent Journal of America, No.6, 1966.
- Veldhuisen, R. van, Euphorbia sectie Triacanthium Jacobsen, Succulenta, Volume 82, No. 5, p. 229 – 233, No. 6, p. 276 – 280, Volume 83, No. 1, p. 18 – 23 and No. 4, p. 150 – 153.
- Vlk, Dr. Vitezslav, Euphorbia Schizacantha Pax, The Euphorbiaceae Study Group Bulletin, Vol. 10, No. 1, 1997.
- Webster, G. L., Synopsis of the Genera and Suprageneric Taxa of Euphorbiaceae, Ann. Missouri Bot. Garden, 81 (1), blz. 33 – 144, 1994.
- The Euphorbia Journal, Vol. 1 – 10, 1983 – 1996.
A grafted plant of Euphorbia awashensis showing the scars of the survived infection and lost sidebranches on the old part of the stem.
Fresh young shoot of Euphorbia awashensis showing the details of spination and marbling of the stem.
A fruiting branch of Euphorbia awashensis.
A mature Euphorbia erigavensis with its typical thick upwards curved branches, in full growth in the collection of the author.
A seedling of Euphorbia erigavensis showing the initial four-spined spineshields when still very young. All species in this group of Euphorbias share this feature.
Habitat picture of Euphorbia margaretae, north of Erigavo, Somalia. Picture Giuseppe Orlando.
Picture of Euphorbia margaretae in cultivation. Picture Giuseppe Orlando
Rather big yellow cyathia with a green glimps are typical for Euphorbia species nova Mrs. Ash.
The cyathia of Euphorbia species 632 are one of the most beautiful coloured in this group of species.
habitus of Euphorbia species 632 with rather straight branches reaching for the sky.