Echinocereus engelmannii and regional forms

[peterb]

I am fascinated by the Echinocereus engelmannii complex and have had the opportunity to photograph almost all of the regional/geographic forms of this complex over the past few years. This group of plants has bedeviled taxonomists for a long time, as one finds out while researching all of the various names that have been published and comparing them with Mesa Garden field numbers, herbarium records and distribution maps, etc. The whole complex has had at least 9 infraspecific taxa described (sometimes at species level, other times at variety or subspecies level): acicularis, fasciculatus, armatus, chrysocentrus, munzii, decumbens, variegatus, llanuraensis, purpureus are some of the names associated with this complex. (I probably missed at least one). In each case, these names were assigned to fairly loosely circumscribed geographical populations.

I have not had a chance to read the original descriptions for all of these names, a project that I am involved in currently, which involves tracking down issues of some very obscure journals such as the Bulletin of the Southern California Academy of Sciences from 1926 (munzii), etc. I only really know them from their associated geographical locales. One definitely gets the sense that this is a complex of plants in the process of allopatric speciation, slowly developing very distinctive characters due to geographical boundaries.

I'll post pics of each form with an attempt at an ID. I could be wrong, of course, either because some forms tend to share characteristics or because my own knowledge is somewhat flawed.

No matter one's taxonomic philosophy, it sure is a cool bunch of plants. I find acicularis to be the least interesting, maybe just because it is the most common form in the Phoenix area, where I live. A funny footnote: in putting this post together, I could not find a picture of anything I would just call "engelmannii." I know I have some photos of some of the Baja engelmannii, and those are just standard. But I can't find them.

peterb

[iann]

I like the spiny California forms. I have to remember to get some seed this winter. I don't have howei or armatus.

[Peterthecactusguy]

all I can say is that you have much more patience then I when it comes to these beautiful spiny plants. I can't ID them for crap however a couple of those forms, while rare are growing around where I live. (E. fascicaulus is growing around here, but for the one I see of that, there are probably 2000 that aren't it and most of them are E. boyce-thompsonii). Anyways interesting study of them, THANKS.

[peterb]

Yes, I left out boyce-thompsonii because it seems it is considered its own species now, or at least not considered under engelmannii. I forget. I also left out nicholii, as it too is considered its own species. They both were named as varieties of engelmannii at various times, however.

I wonder how I would do in a test, identifying these without any habitat information. Probably not so well. It is particularly the combination of interesting characters and particular geographic locations that make them somewhat easier to identify.

peterb

PS- re: boyce-thompsonii, it looks like it is not mentioned at all in the Flora of North America. At least, I can't find it.

[Peterthecactusguy]

lol PeterB, if you gave me a test on those forms I would fail. I can't tell any of them apart. I consider boyce-thompsonii to be a separate species, same as nicholii and actually I forgot that both of those were under engelmannii at one time. Still a very fascinating subject. I actually wish I knew more about these plants because there are so many around where I live. So north, and some south and a lot around here. I guess I need to travel more in AZ and look at the different populations some.


(edit) looked in SEINet they have it listed as E. fendleri var boyce-thompsonii

[MJPapay]

Nice photos of an intriguing species.

Ever since I obtained and grew E. boyce-thompsonii the lure of this tribe was upon me.

Now I have E. engelmannii fasiculatus, E.e. variegatus, E. nicholii, E. stramineus, plus mixed seedlings.

I wish I could grow E.e. armatus and E. acicularis types, but figured the climate here was too wet and humid so never tried.

[Peterthecactusguy]

haha Nice MJpapay you grow more Echinocereus than I do. Of course the E. boyce-thompsonii are all over the place around me, and I have gotten several cuttings, and a rescue.

[vlani]

My feeling there are only three forms that deserve name recognition.

One is House Rock valley plants. It is a notably smaller form, spines also shorter, and it blooms a smaller plant. It is common further North, I've seen it just outside of Great Basing NP in Utah, and I think Tonopah plants are of the same king, not sure if I remember it right.

One form is South CA plants, big presence at South of Anza Borego SP in CA. They seem having fewer ribs, a bit more space between areoles. Easier to recognize in plumed up state. Large spiny plants, I've seen only yellow spines but I doubt it is persistent. Flowers are a bit lighter shade of pink but not quite like nicholii.

Phoenix area has bunch of engelmannii X fasciculatus plants, looks like a good gene sup - but that is a different category all together. E. apachensis is of this kind.

Everything else I've seen is a bunch of very spiny plants, dark or yellow spined with always white spines in the areole, persistently mixed colors everywhere. There is some spine variation but I'd attribute it to environmental differences. The drier the area the spinier the plants, and in the shade spines are reduced as we know. Sometimes spines are more curly sometimes they are more straight or arching down, usually with lots of variation at the same locality. All those plats when grown in collection are usually look very similar. To make them develop same nice spines they have to be raised slowly, flowering plant from seed will take something like 20 years vs. normal 7 to 10.

Interesting part about E. engelmannii is how common it is in SW US and how uncommon it is in collections worldwide. Very beautiful and very overlooked plant. My guess if it has been a resent discovery every collection would of have it

[A. Dean Stock]

There are areas on the Beaverdam Slope in extreme southwestern Washington Co., Utah where these plants are very abundant and in an acre or so you could find most of the more spiney forms of various colors shown above. To add to the confusion, there is likely a diploid form in northern Arizona/swUtah that may or may not be the form originally named var. purpurea. The plants in House Rock Valley are similar to those that occur across much of the Arizona Strip and north in to Utah at elevations above 4000ft.. I'm not an Echinocereus taxonomist so I leave these to Marc Baker to work out.
Dean

[peterb]

Dean, I didn't know Baker was working on engelmannii. I can totally see why none of the variety/ssp names are currently accepted. The gestalt jumps out at one in the field, but on closer inspection, the details are pretty thin stuff to hang a name on. It is remarkable to encounter these in their extreme forms. They are very convincingly worthy of a special designation. It is also revealing to encounter them in cultivation or in a more blended or confusing population. Then one wants to throw all the names out. haha.

peterb

[CactusFanDan]

A very nice couple of plants there. You can see why they've been allocated different names in the past. There are certainly distinctions between them all. Very interesting.

You could also pose the question: at what scale does taxonomy become irrelevant? And why isn't this scale the same in all organisms? (obviously owing to practicalities, but it's an interesting thought)

[A. Dean Stock]

They certainly are confusing but likely they are very understudied. Most of what FNA represents is the lack of data and the rather extreme views of the most dedicated "lumpers" in the world. The fall back position in taxonomy, when faced with little data, is to simplify the field.
I believe that Marc Baker is still working on E. engelmannii at times. I'll ask him. Lack of any funding for general cactus research is the limiting factor except for retired people (like me).
The many forms and hardiness of E. engelmannii makes it one of the best plants for out door cactus gardens.
Dean

[MJPapay]

However one wishes to look at their taxonomic relationships, I hope (as I'm sure do others who enjoy seeing variation) that the populations will be recognized, seed collected and plants made available - and not all forgotten because they carry one name. And, no - I am not suggesting anyone wishes the different populations or spine forms to be forgotten. I do worry that it can happen though. Why I worry about it I don't know.

[A. Dean Stock]

Peter, that nice plant from the Grand Canyon Skywalk area may not be E. engelmannii. You should have Marc Baker take a look at the photo.
Dean

[peterb]

aha, interesting. I will do that.

peterb