E. ingens?

[Boo Hollow]

Stan - Not being an expert in Epigenetics but understanding the theory, I do not see how growth due to environmental influences relates to cellular differentiation based on the aforementioned theory. Availability of nurtrients and water does not necessarily equate to a genetic modification. Like turgor pressure in a plant because of available water does not mean there is a gene expression going on, just turgid cells. To stretch the concept to include whether an Opuntia cladode is wrinkled due to dehydration is a different plant than one that has satiated its water uptake would be silly. A gentleman named Paul Kammerer published a tome titled "Inheritance of Acquired Characteristics" in 1924 which played on that same theory that environmental influences could induce genetic changes that passed on to the offspring. It was revolutionary at the time and was later found that he had falsified the information and he subsequently killed himself over it. This was the topic for Koestler's book, The Case of the Midwife Toad. Increased vigor due to more ideal environmental conditions may create a mutation that is passed on, but I wouldn't be as bold to state that I can create a new cultivar of plants just because I have provided the ideal growing conditions for a given plant.

My reference was that morphological variations occur when a plant is provided with ideal or better than "natural" watering, nutrient and sunlight exposure. The seeds from these bloated plants does not create bloated seedlings nor new morphological forms. Just because my Dudleya parent plants are well cared for has not expressed itself in the millions of seedlings I have grown from same. I just don't see it carrying over. With respect to the Euphorbia or other plants, shouldn't one consider that the plant may have gone through some rotational exposure (change in orientation) to the sunlight that may have changed auxin concentrations on a given area of the plant that creates new growth or structure (excess ribs or branching). Since the ribs probably serve as a structural reinforcement to the columnar body, wouldn't an increase in mass increase pressure on meristem tissues (it does increase auxin concentrations) which would result in more ribs for support? Changes in auxin concentrations would also increase branching and with increased branching - more available surface area for photosynthesis, thus more growth and so on. Just a thought.

[Stan]

No expert on the theory here either..but all those changes of cause and effect on plants you went through are what drives evolution.Epigenetics I think, fills that area of subspecies and why plants diverge sometimes invisible to the eye,but to botanists are distinct. Evolution and Epigenetics overlap so much I guess it would take a scientist interested in both AND botany and not me to answer for sure. But,its a thought!

[amanzed]

It's been said before, but even without drawing neo-Lamarckian heredity into the question, cultivation exerts additional pressures of inbreeding and selection bias: (for vegetative propagation) selection for clones which branch or offset readily, and (for any commercial propagation) selection for populations which grow profusely in cultivation (or simply grow well at all). Not to mention the nurture and propagation of traits which would never survive in the wild.

These selection pressures may quickly push a taxon in cultivation far away from its genetic and morphotypic "center", judged against populations in habitat.

Getting back to epigenetic factors, we hobbyists are so attracted by the "magic" of vegetative propagation that we often assume that cuttings are (more or less) new copies of the same plant (except for an absent caudex here and there) rather than thinking of them as fragments of very old plants. But I seem to recall from a recent news feed (pointed to here) that researchers found in one instance that very old clones had less success with sexual reproduction. This certainly got my attention and challenged my assumptions about the magic of vegetative reproduction!

--dean

[Boo Hollow]

Dean - Well put. However, the term nurture of defects to survival would support a "human" touch to the evolutionary theory. Breeding and interbreeding create new "breeds" and "cultivars" but not new species?!?

I look at what Masters wrote in 1869 in his Vegetable Teratology about birth defects in plants being carried forward if they survive. Remember that this was pre Watson & Crick and Franklin, so the method of chemical teratogenesis was not understood. If a defect survives that is not the result of recessive gene expression but rather through another forced mutation, does that mean it will express itself again in the offspring? Many articles state that taking offsets from variegated plants, for example, will result in plants that frequently revert back to the normal parent plant. So how would one tie these changes moving forward as an evolutionary step or leap into the morphological variation of the future plants. I think it is akin to birth defects in humans. Cleft palate does not always carry forward, so would cristate or monstrose forms follow the same rules?? It is a problem with cell division in one form or another.

Getting back to the original statement of plants being forced to change due to cultural practices, the visible expression we see may not really represent the true holotype or lectotype but may rather be a paratype? The plant being used as the holotype may have been the personal favorite of the original describer and one of a series of paratypes at the describer's disposal. I think this is where I get confused on the identification of the true species and its description. I have seen this arguement presented when trying to determine whether or not the California Tiger salamander was a simple subspecies or species. How many plants that we are basing our nomenclatural descriptions on have had DNA analysis conducted on them. The 200+ year old herbarium specimen used to set the stage moving forward would probably not hold up today under the same scrutiny of classification standards. Just because the name was used first, does this always make it the right name??? Isn't that why we have a lot of synonyms?

Open thoughts. BTW. The Masters book has been reprinted and is a great read. The original is quite rare and expensive and I sure wish the reprint had been available prior to me shelling out those bucks for the original. Think of all those sports and cultivars I could have purchased.

Cheers!

[Stan]

I know you remember in the 80's Steven Gould put out there that evolution wasnt always slow and steady-it "jumped forward" sometimes in a relative fast period...So I'm thinking that for example one type of epigenetics in plants might be etiolation. Imagine a palm in a very comforting environment,but very dark..those seedlings that could stretch to the light while still being healthy..well, That's your eventual climbing palm. It didn't adapt to low light, it "learned" to stretch..epigenetic like.

[agavemonger]

Stan, the plant in the photo you posted is classic Euphorbia ingens.

The monger

[Stan]

You might be right monger,it was labeled E.abyssinnca. As a matter of fact, the ONLY tree Euphorbia's I have seen for sale in the SF bay area are labeled abby or the white E.ammak. BUT,Monger,I have thought it strange that the most famous tree Euphorbia of them all-E.ingens would be non existent here. It wouldnt make sense.
I have another question-guerilla's photo of a multi-MULTI branched tree Euphorbia? Is that Ingens too? Because a neighbor of mine has one identical to his-and its very fast growing. So,I am perplexed-lol...why does mine branch so high and his is like a tree bush?

[GermanStar]

guerrilla gardener's photo shows the same type plant as mine, the identity of which we are attempting to ascertain. If you look at the OP, I posted a pic of my plant, asking if it might be E. ingens. The difference in branching is the difference between a bush and a tree.

[agavemonger]

Dare I even go there?!

Stan:

1) It wouldn't

2) NO!

3) Because they are two different species!!

The Monger

[Stan]

Ok,ok,..mine IS ingens you say..so that's nice to hear I guess. And back to square one on G.G.s and my neighbors and German Stars. Good,that's settled-lol...

[agavemonger]

[Ron]

Well, I don't really know squat about which is ingens and which is abyssinica. The only thing I do know is that years ago, before I posted the images that I posted on davesgarden.com, I sent the very same closeup images to Frank of the euphorbia.de site. I think I had an online posting discussion with palmbob about this at the davesgarden site. Anway Frank said this image was E. abyssinica and then went into a bunch of lingo I didn't understand:



To me it's very distinctive. It's the biggest euphorbia I have...I'd say about 25 feet tall at least. The spines are tiny. It has a non-shiney surface. It leafs out little to none at all. And the color is a greyish-green. And also, the stems go every which way and twist. Now that's the one Frank said was abyssinica.

This is the pic of the other one I sent to Frank and he said this one was ingens:



Frank identified this one as E. ingens and then also proceeded to go into lingo I didn't understand. My own description on this one is that it is about 15 feet tall (at least mine is). It is heavily stiff-branched from a couple of feet above the ground. The spines are 2-3 times bigger than the abyssinica one above. It is shiney bright green in color. Once it gets to a level of maturity the growth of the branches are upright, dense, and regular. And it's a fast grower.

Who knows? Maybe I accidentally switched them around (I don't think so though). But I do know that they are both very, very different looking from one another.

Here are the two descriptions from Jstor but I always have problems visualizing the technical lingo stuff.

Euphorbia ingens
Taxon description
FZ, Vol 9 Part 5 Author: S. Carter & L.C. Leach

Candelabriform succulent tree to 5(7) m high; trunk stout, to 22.5(30) cm in diameter; crown flat-topped.Branches usually whorled, spreading and curving upwards, usually exceeding the trunk apex, 3(4)-angled, regularly constricted; segments 6–8 × 5–7 cm, ovate to circular; angles stoutly wing-like, with shallow tubercles c. 1 cm apart along the margins.Spine shields forming a continuous horny margin to 8 mm wide along the angles; spines stout, 2–7 mm long, diverging; prickles rudimentary; rudimentary secondary spines flanking the flowering eyes on young growth.Leaves minute, quickly deciduous.Cymes 1–3 from each flowering eye, lateral cyathia vertically arranged; peduncles 7–10 mm long, cyme branches 5–8 mm long, stout to 4.5 mm in diameter; bracts c. 7.5 mm wide, broadly elliptic, obtusely keeled, usually ± split.Cyathia 4–5 × 10–11 mm, with cup-shaped involucres; glands 2.5 × 5 mm, reniform, spreading, closely touching, yellow; lobes c. 2 × 3 mm, subquadrate.Male flowers c. 60: bracteoles fimbriate; stamens 6 mm long.Female flower: perianth irregularly dentately 3-lobed; styles spreading, 2.25 mm long, joined up to two-thirds.Capsule 9–18 × 15–24 mm, obtusely lobed, truncate at the base and apex, exserted on a stout, curved pedicel to 13 mm long.Seed 4 × 3.5 mm, subglobose, olive-brown, mottled with a waxy coating.




Euphorbia abyssinica
Taxon description
FZ, Vol 9 Part 5 Author: S. Carter & L.C. Leach

Tree to 10(30) m high; trunk simple to c. 90 cm in diameter; bark rough greyish.Primary branches ascending, rebranching irregularly and ± densely to form a spreading rounded crown; branchlets fleshy, 3(4)-angled, 5–17 cm wide, ± constricted at irregular intervals into oblong segments 15–40 cm long; angles deep and thinly wing-like, 2–7 cm wide, margins of the angles straight to ± sinuate bearing tubercles 1.5–3 cm apart.Spine shields rounded, to 5 mm in diameter, eventually extended to 5 mm above the spines to enclose the flowering eye; spines stout, 1–3 mm long; prickles absent or rudimentary; spine shields and spines becoming corky and disintegrating.Leaves persistent on young growth, to 15 × 6 cm, obovate, fleshy, midrib keeled on lower surface, base tapering to a petiole c. 1 cm long.Cymes 1 or 2–3 in a horizontal line, or occasionally 4 crowded together, 1-forked lateral cyathia vertically arranged; peduncles and cyme branches stout, 3–4 mm long; bracts rounded, 4 × 7 mm.Cyathia c. 4 × 7 mm, with cup-shaped involucres; glands transversely elliptic, c. 2 × 4 mm, margin undulate, not quite touching, yellow; lobes c. 2 × 3.5 mm, transversely elliptic.Male flowers: bracteoles spathulate, plumose; stamens 6 mm long.Female flower: perianth irregularly divided into 5–12 lanceolate toothed lobes to 6 mm long; styles 3.5 mm long, joined at the base, apices thickened, bifid.Capsule to 12 × 16 mm, subglobose, fleshy, red, hardening before dehiscence to become obtusely 3-lobed with woody walls 2–3 mm thick; pedicel stout, 3 mm long.Seeds 4.5 mm in diameter, subglobose, slightly laterally compressed, yellowish-brown, speckled, smooth.

-Ron-

[Stan]

Ron's description is identical to my post. My labeled abby had a heavy trunk, didnt branch until tall,has dark spines,twisty branches. Not especially fast as my E.ammak is its a bit faster...but my neighbors plant that I have seen go from dish garden 6" to 8' in 4-5 years and full of branches to the base,seems Ingens like.

[GermanStar]

Euphorbia abyssinica
Taxon description
FZ, Vol 9 Part 5 Author: S. Carter & L.C. Leach

Tree to 10(30) m high; trunk simple to c. 90 cm in diameter; bark rough greyish.Primary branches ascending, rebranching irregularly and ± densely to form a spreading rounded crown; branchlets fleshy, 3(4)-angled, 5–17 cm wide, ± constricted at irregular intervals into oblong segments 15–40 cm long; angles deep and thinly wing-like, 2–7 cm wide, margins of the angles straight to ± sinuate bearing tubercles 1.5–3 cm apart.Spine shields rounded, to 5 mm in diameter, eventually extended to 5 mm above the spines to enclose the flowering eye; spines stout, 1–3 mm long; prickles absent or rudimentary; spine shields and spines becoming corky and disintegrating.Leaves persistent on young growth, to 15 × 6 cm, obovate, fleshy, midrib keeled on lower surface, base tapering to a petiole c. 1 cm long.Cymes 1 or 2–3 in a horizontal line, or occasionally 4 crowded together, 1-forked lateral cyathia vertically arranged; peduncles and cyme branches stout, 3–4 mm long; bracts rounded, 4 × 7 mm.Cyathia c. 4 × 7 mm, with cup-shaped involucres; glands transversely elliptic, c. 2 × 4 mm, margin undulate, not quite touching, yellow; lobes c. 2 × 3.5 mm, transversely elliptic.Male flowers: bracteoles spathulate, plumose; stamens 6 mm long.Female flower: perianth irregularly divided into 5–12 lanceolate toothed lobes to 6 mm long; styles 3.5 mm long, joined at the base, apices thickened, bifid.Capsule to 12 × 16 mm, subglobose, fleshy, red, hardening before dehiscence to become obtusely 3-lobed with woody walls 2–3 mm thick; pedicel stout, 3 mm long.Seeds 4.5 mm in diameter, subglobose, slightly laterally compressed, yellowish-brown, speckled, smooth.

Sorry, I don't understand how that can be correct.

[Ron]

Sorry, I don't understand how that can be correct.

Sorry, I can't help you there. I just went down to look closer at both plants and they both appaear to have four ridges with spines up and down them (if that's what they mean by four-angled.

Further, here's what the Jstor site has about Euphorbia acrurensis:

* EUPHORBIA acrurensis N. E. Br. [family EUPHORBIACEAE],
* EUPHORBIA abyssinica Schweinf. [family EUPHORBIACEAE], in Bull. Herb. Boiss. vii. App. ii. 317, partly; Pax in Engl. Jahrb. xxxiv. 77, partly.

Information Arborescent, succulent, spiny.Branches of the dried specimens seen 7-angled and about 4 1/2 in. in diam., with the solid central part about 1–1 1/4 in. thick and much less in diam. than the angles are broad (seedling plant 3-angled and 1–1 1/4 in. in diam.); angles wing-like, 2 in. broad and 2 lin. thick at the edge in the dried specimen, with triangular channels 1 3/4 in. deep between them. Leaves not seen. Spines 1 1/2–5 lin. long, in pairs, diverging, stout at the base, blackish-grey on the seedling, becoming grey with darker tips with age, on suborbicular horny shields 3–4 lin. in diam. on the mature branch, much smaller on the seedling, not connected by a horny border along the angles, becoming grey with age, with the flowering-eye touching or subincluded in their apical part. Cymes (detached, but distributed with the stem-sections) on peduncles 1/4– 1/3 in. long, bearing 3 involucres, the middle one sessile and the two lateral on cyme-branches 1 lin. long, glabrous. Bracts thin, adpressed, broken, but apparently suborbicular and about 3 lin. long and 2 1/2–3 1/2 lin. broad, very concave. Involucres 1/4– 1/3 in. in diam., cup-shaped, golden-yellow (Schweinfurth), with 5–8 glands and 5–8 transversely rectangular fringed lobes, glabrous; glands 1 1/2–2 lin. in their greater diam., erect in dried flowers, transverse, reniform, with the middle of the inner margin turned in and forming a small lip, or crescent-shaped, with the inner margin concave, in dried specimens with the outer margin more or less incurved. Ovary subsessile and included when young, in fruit exserted and curved to one side on a short stout pedicel, glabrous; perianth fleshy, with 3 lobes 2–2 1/2 lin. long, deeply cut into 2 or more filiform segments or entire and subulate-acuminate, in fruit reflexed and the segments often broken off; styles 1 3/4–2 lin. long, shortly united at the base, rather stout, slightly thickened and minutely 2-lobed at the apex. Capsule 5–6 lin. long and 8–10 lin. in diam., deeply 3-lobed as seen from above (globose-triangular and reddish when alive, Schweinfurth), glabrous; cell-walls very thick and woody. Seeds slightly compressed-subglobose, 1 3/4–2 lin. in diam., with a slight furrow on one side, smooth, light grey or whitish, slightly marbled, with a dull surface.
Distribution Nile Land Eritrea: vicinity of Acrur, Schweinfurth, 1351, partly!


Notes There appears to be some confusion with regard to the succulent tree-like Euphorbias growing in Eritrea which Schweinfurth and others have referred to E. abyssinica. None of the specimens which I have seen belong to that species. Schweinfurth and also Pax certainly include two or more species under that name. The former states that it varies in appearance, growing 10 to 30 ft. in height, sometimes with a short trunk and a large crown of longer branches, sometimes with the trunk as tall as the obconic flat-topped crown. Seedling plants are 3-soon becoming 4-angled. Young unbranched trunks are sometimes up to 9-angled. The main branches are 4–6 in. in diam. and 6–9-angled and the secondary branches about 5-angled. Leaves of young shoots and seedlings are up to 3/4 in. long, oblanceolate, slightly cuspidate at the apex, cuneate at the base, passing into a petiole. The spines are rarely more than 4 lin. long, grey with black tips, in pairs about 7 lin. apart. I do not know if this description refers to the Acrur plant or not, as I have not seen leaves of the plant I describe, but only a seedling plant, with stem-sections and loose flowers and fruit. I therefore restrict my description of E. acrurensis to the Acrur plant with 6–7-or more angled stems, to which I suppose the pedunculate cymes distributed with the stem-sections may belong, Schweinfurth & Riva, 1351, collected in 1892 (not 1891). Unfortunately fragments with sessile fruiting cymes have also been distributed under the same number and date, but the structure of the spine-shields and flowering-eyes on the scraps of stem-angle with these fragments and that of the cymes and involucres is identical with those of E. disclusa, N. E. Br., to which species I believe they belong. Schweinfurth 1351 of the 1891 collection is probably a variety of E. Erythrææ, N. E. Br. All these have been distributed as E. abyssinica, Raenschel, from which they differ totally in having the branches constricted into parallel-sided or slightly conical (not elliptic or orbicular) segments.

-Ron-

[agavemonger]

Hi Ron!

Your 1st photo is of a plant we've always sold in the trade as Euphorbia ingens. This is the "mature" form, which looks quite different from the young, mottled, almost variegated-looking seedling or immature-form cutting-grown plants. Plants grown from even small cuttings of the "mature" form will usually retain the "mature" form growth charachteristics. The immature form is much more attractive and "shows its spines" more readily.

Your second photo is of a plant we've always sold in the trade as Euphorbia ammak. (Compare this plant with the ubiquitous Euphorbia ammak variegata; they are identical save for the variegation). The green or "normal" form is relatively rare in cultivation, as cutting stock on Euphorbia ingens is much more readily available. This may partially account for the confusion.

Euphorbia abyssinica is quite different from these two. One of these days I'll get around to posting some pictures. It is a massive, deep dark-green plant with many more than five ribs. I believe there can be well in excess of 8! It is very rare in cultivation, which probably accounts for all the confusion. I don't believe I have ever seen one correctly labeled in a public garden!

I am astounded at the high degree of controversy over what are three clearly discernable, easily distinguishable species. It is really quite basic! There is a great hint about the mystery "fourth" species we've been discussing here in the Jstor descriptions you posted! I am almost certain that there may even be an even more mysterious, "fifth" species masquerading as E. abyssinica. Much more to come later...

The Monger

[Stan]

Then those world famous melted Tree Euphorbs at Lotusland are ammak or abby? Gary Lyons describes E.ammaks at Lotusland as a "true" identification,then confusingly I.D. those planted along a pink wall with twisted branches as a "relaxed form" of E.ingens!. Everything posted here sounds more like abbys. And in his book 'Desert Gardens' a closeup photo of what he calls E.ammak with fruit look identical to Ron's E abby's. signed,MR.I.M. Confused.

[agavemonger]

Hi, Stan!

Good observations!

Those "relaxed" Euphorbias with the wavy arms have always been problematic. I believe they are not Euphorbia ingens, even though they have somewhat of a similar look. They are most likely yet another unknown species, as they are truly different and I have never observed any "sort of" intermediates. They either "wave around" all over the place or they don't. E. ingens is very vertical and formal when well grown. With large plants of E. ingens, any branches that start to lean at all for whatever reason (high winds from a major storm, for instance) just snap off and fall to the ground. There is most likely a description of this species somewhere in the old reports, as it is very distinct and would definitely stand out as different in situ. Any researchers out there?

I don't remember the "melted" plants @ Lotusland; Do you have pictures by any chance?

One of the problems with identifying tree Euphorbias is that they tend to be grown hard and ignored, and end up all kind of looking alike. When they are grown right next to each other, the differences are more easily discerned.

Very well grown smaller plants, when grown by the same grower under the same ideal conditions are very easy to differentiate.

In Ron's first picture above, notice that the ribs are straight and the spines have receded to mere prickles. This is classic "mature form" E. ingens.

Notice in the second photo that the ribs are very wavy and well-armed even though the plant is quite large. This is typical growth for E. ammak. Notice also how similar the basic form of the plant looks to E. ammak variegata, which one can observe all over the place.

I would very much like to get a cutting from each of these plants we are discussing this spring. I will grow them under the same full-sun conditions and then post photos of them next to each other when they have broken into new, aggressive and healthy growth. That is one way to be sure about what we are pontificating about. Any takers? All I need is a small piece!

The Monger

[Stan]

The "relaxed" ingens were what I meant by melted plants. And you know monger? In all the years of looking at the net,I haven't seen another garden with such a large grouping of those as at Lotusland. Maybe one in Monaco's great garden,and a couple in San Diego. It seems like it would have to be more than coincidence that Ganna Walska who specialized in odd plants would have aquired those plants that in time became twisting, writhing, tree Euphorbs.
I have to wonder who came across those plants for her-and from where? And is there even now a source? Do all the others on the net originate from Lotusland? You would think such showy unique plants would get a DNA test..but, I guess Maury Povich gets preference..

[agavemonger]

Sounds like you're UP for a little sleuthing there, Stan!

I can imagine a scenario where the Madame batted her eyes at the prince of Monaco, who promptly procurred her a cutting which headed back to the coast well protected in her steamer trunk!

It would be very interesting to attempt to sort this one out. I never really thought much about this plant over the years, as we always thought of it as kind of an ugly plant that would be difficult to deal with. Sort of reminds me of the apple trees in the Wizard Of Oz!

However, I would love to get a cutting from one and see how it performs as a small plant under nursery-controlled conditions. I would be very surprised if this plant was not a species...

They are around in many places; I just can't remember where! Mostly in old gardens in older homes in older neighborhoods, as large wandering-armed gangly trees. Does anybody have photos to post? This is another mystery that sure would be neat to get to the bottom of...

The Monger

[GermanStar]

Just got back from Home Depot, where I stumbled upon a real live 4½' tall dark green, white-spined, 8-ribbed E. abyssinica. It was a looker, alright! First one I've seen.

[agavemonger]

Hi German!

Did you pick one up? This plant (if from Altman Specialty plants) is a descendant of the stock I sold them some fifteen years ago! I saw some at their retail outlet, so I guess I'll have to "buy a few back" and start growing them again!

The Monger

[GermanStar]

Tempting, having already added a couple of Zone 10 Euphorbias to my landscape this year, I thought it prudent to see how they weather a Zone 9 winter before adding any more. Had I known it was your progeny, I might have decided otherwise!

[palmbob]

Sadly I cannot add much to this discussion of these plants from a scientific or intelligent-sounding point of view, at least in terms of what abyssinica or acurensis is. You can peruse the Euphorbia journals and find several photos of abyssinica which sure appear to be unrelated plants. Either it is a variable species, or even the 'experts' don't know exactly what is going in. From my own point of view, Euphorbia abyssinica has always been a big mystery, which is odd since its name is so commonly used in the literature, and plants labeled as such always show up in nurseries (not that that really means anything). I have never seen one in person, or if I have, it was not identified as such. However, one thing that seems consistent in the photos of this plant, at least in the journal Euphorbia, is that it is always more than 5-6 sided. Thorns look like E ammak thorns only very dark (almost black). But what is frustrating is that photos NEVER show the whole plant... just close ups. So I have no clue how big it gets, what sort of shape it obtains, etc. Color is always dark green.

The following are what i see and have photographed of the other plants in this discussion. And though I am not schooled in botany or have a well developed vocabulary, I do have an artist's eye and am pretty good and identifying things once I know what they are. It would help if I could then scientifically describe what I saw to others.. but my primitive, naive words will have to do.

Plants identified as E acurensis, whether at botanical gardens or nurseries usually look the same, so I at least feel comfortable identifying plants as such, whether that is a synonym or not for abyssinica (which it may be... but if it is, the plants identified as acurensis are then indeed something else as the two cannot possibly be the same thing). These plants are upright, never drooping and are 'tight' in terms of appearance- my vocabularly sucks, so what I mean by that is all the branches are relatively close together, not nearly as much as lets say Euphorbia trigona, which is 'really tight'. These plants are usually 4 sided though when young they seem to start out 3-sided... again, maybe those are different plants? They are always thinly fleshed (meaning there is less 'flesh' to them than lest say E ammak or ingens). The 'thinness refers to the columns as the trunk develops into a thick, sturdy and square in cross section, almost rounded between the rows of spines... I have never seen a tall one (over 20') but then I have never been to AFrica either, so there could be giant ones there. The spines are sharp, thin (only plant discussed here with thin spines) and protrude about 0.5-1cm, and are very annoying. These plants are always a bright green to sometimes deep green. I know that is about as unscientific a description as you will ever read anywhere, but it is how I see things, and I find this a very recognizable plant- not a lot of variability. No wavy edges (as in ammak or sometimes ingens), never spineless (as in old ingens), never droopy, no branches pointing laterally, always thin etc. These produce leaves at the right time of year and with enough water- the leaves can grow up to 2" long (unlike E ingens) but I only see plants with them at the tops of the columns (sometimes I see E ammaks grown in shade with leaves running nearly their entire lenghts). Leaves are very thin and hardly succulent at all.

On to Euphorbia ammak. This plant is also confusing as there seem to be a lot of plants that are ammak-like. This may mean this is a highly variable species or that I am seeing hybrids, cultivars or something else entirely.

There are of course the very common variegated forms, all which look fairly alike. Though it might be woth noting young plants can look a lot different than old ones. Young plants have a lot more 'wave' in their branches and the spines are more prominent (maybe because of the wave pushing them out farther). This plant can be somewhat 'thin' (less meaty), but never as thin as E acurensis) or thick- nearly square in cross section in older specimens. As far as I can tell, this is also a 4- sided plant, with rare 5 sided branches now and then. Spines are very short (0.2-0.5cm), sharp and pale in color. Older taller plants seem to have even shorter spines, to the point one can pick up a section with bare hands and not be annoyed by them. Waviness is one of the distinguishing features that makes these so ornamental, but waviness is not consistent and older plants often have very little wave in the rows of columns. Monstrose forms of E ingens can sometime be confused with E ammaks, but tend to have a much smaller diameter. These grow very tall and often drop branches. Branching is usually upright but sometimes I see branches off to the sides... but it is rarely as irregular and messy looking as huge E ingens can get. Fruits are rounded (and variegated). Leaves are usually seen in new growth only, but shaded plants will often retain short, somewhat succulent leaves a long ways down the columns.

The green forms of what I call ammak do not look like the same species sometimes, as many have more than 4 sides. Most are less robust. Some have mild variegation, some are dark green. I have no idea if these are really E ammaks or some hybrid with the elusive abyssinica, or with ingens or are monstrose creations of cultivation. Sometimes I wonder if some of these are indeed the 'rare' E abyssinicas. I am not an stable ground with these plants, and I will show you several photos below to show you what I mean. I have never seen one in fruit. Leaves are commonly seen on some of these and never on others. Some have very thick growths of leaves, particularly if shaded. I have no idea how big these get as I have rarely seen one grown in a botanical garden.

E ingens is an easy plant to identify as it, like E acurensis (or what I call E acurensis) and the variegated E ammak, is not a highly variable plant. UNLESS you include that weeping thing at Lotusland (see photos below). It has a very thick flesh, rounded columns (not sharp as in E ammak and acurensis) and spines are so short sometimes they are immeasurable. Spines are dark brown to black. This plant is 4-5 sided, though mostly 4-sided. It is a monster and grows very tall. Branching is frequent, often with branches growing laterally or even pionting down (though I suspect that is more a function of their extreme weight and just not completely falling off). Fruits are reddish and triangular in some plants and spherical and yellow in others (two different plants? or what?). See photos below.

First two photos are of plants that are four sided while next two are three sided- age difference, variation, different plants? Last photo is my own and it is 'wavy' thanks to my torturing it... it was not wavy at first, nor it is today. Spines are consistent with all four plants (very sharp and annoying).

[palmbob]

Here are, for fun, some E ammak photos, not so much for education, but I want to show you plant photos...