variation in M stella-de-tacubaya

I keep my plants at a high minimum temperature (because of the Stapeliads in my greenhouse). This means early flowering of several plants. This M stella-de-tacubaya is in flower at this moment. It was a sunny winterday but flowers do nog open very wide. Both of theh plants illustrated are from the same batch of seeds and came with number P 307.

Wiebe

Hi wiebe,

Well done in keep your plants going.
Spine variation and wether to have or not to have spines is more common than we think in many species.
In the pass I have brought a number of plants of this species and killed them all within six months. Last year I obtained seed from a lot of different sources, Steven Brack has a number of field collections of this species under the name M.gasseriana but he never collected the true M.gasseriana. The seed was sown last year and has given good results so hopefully I will have better luck at growing on the plants.

That's an early start, even for an early flowering species!
My greenhouse is kept at 5C, apart from a small area for the guerreronis, mammilaris, nivosa and beneckei types. So it will be a while before I get buds appearing and opening.

You raise an interesting point about stella-de-tacubaya and gasseriana naming. As we know there has been a lot of ocnfusion of these names in the past, so I was wondering if we could get a list together of what field numbers are true stella-de-tacubaya and what are gasseriana?

I'll start simply by listing the field numbers and locations of my plants named as stella-de-tacubaya:

ROG081 from DGO-1, Peñon Blanco, Dgo. I see it was named as gasseriana aff.
ROG085 from w. Viesca, Venustiano Carranza, Coah.. Originally named as chica.
ROG720 from MEX-34, km 73.2, Nazas - Rodeo, 1312 m, Dgo.. Named as gasseriana.
SB1161 from west of Mapimi, Dgo. Named originally as gasseriana.

Named as m. gasseriana:
MG651 (not a FN) from Rio Nazas, Dgo
ROG621 from MEX-34, km 77.4, 1 km n. Eufemia Zapata, 1292 m, Dgo
SB1161 as above!
SB447 from El Palmito, Dgo, in Pilbeam as stella-de-tacubaya (gasseriana).

These are the names under which I acquired the plants or seed, not necessarily what they really are. It is my understanding from what has been written that most of the plants from Durango are likely to be stella-de-tacubaya rather than gasseriana. Bt I am happy to be proved wrong.

It would be helpful to us all, I'm sure if we can arrive at some kind of common understanding. As Tam says, presence of central spine is a variable feature of the Lasicanthae and other Series as well - look at M. nana ssp duwei etc that we've seen on another thread.

Open to all contributions.......

At the moment all I will say is that for me any plant from Durango is M.stella-de-tacubaya. I do not know about Zacatecas and southern Chihuahua.
M.gasseriana comes only from the south west corner of Coahuila. Here spined and non spined plants can be found and it is easily confused with hooked spined forms of M.lasiacantha magallanii.
Wotler wrote an excellent article on the subject in the AfM and reprinted in the UK Mamm Society Journal and I will wait to see what he has to add before providing field numbers of which I have many.

That's sort of where I am as well, Tam, and agree that Wolter's articles were excellent.

However, it is perhaps a little too simplistic to say all plants from Durango are M. stella de tacubaya.

Rog 085 from Viesca, Coahuila is little more than 60km from Torreon on the border between Durango and Coahuila, which is where M. viescensis comes from. The land between these two towns is mostly agricultual now, so we may not now be able to say what might have been there.
SB1161 is from some 45km north west of Torreon
SB447 is from some 180km west of Torreon.
Nazas is some 120kms from Torreon.

The distribution of plants don't obey artificial man made boundaries, if anything they obey natural features, mountains, valleys, rivers etc. I can't see any major separating range on the border of Durango and Coahuila around this area that would suggest a sharp delineation. That is of course looking at Google Earth, as I haven't actually been to that part of Mexico yet.

In my mind the area were M.gasseriana is found is to the east of Torreon out to San Redro de las Colonias / Emiliano Zapata ( not Eufemio Zapata in Durango ) / Cerro Bola and down to Viesca.
To me, all of the field collections I have seen and which were made west of Torreon have all looked to be M.stella-de-tacubaya.
I would also point to the work untaken by the Fitz-Maurice's on this subject, there was an article in th UK Mamm Society Journal a few years ago. They placed M.stella-de-tacubaya has a subspecies of M.lasiacantha while maintaining M.gasseriana has a species.
The question would seem to be how far west from Torreon does M.gasseriana extend, if at all.

Yes, that indeed is the question, Tam. You have put it very well. It would be not unusual to find some intergrading of forms one the boundary of distribution areas.
Hmmmm....

I looked up the Piltz number, it belongs to M. stella-de-tacubaya from Rio Nazas. In that region you can find plants with hooked centrals growing less than a meter from plants without any centrals. So, Wiebe, what you have is fairly common. But don't be surprised if next year the non-central spine plant will develop hooked centrals.

Wolter.

This is the plant I view has M.gasseriana, RS 571



ThIs is the plant I see has typical Stella de tacubaya, SB 1161

Nice little plants aren't they!

here's one that was called viescensis, which I believe is now included in gasseriana.



and one of my SB1161



In addition to the geography, I believe that if the plant has separated clusters of radial spines and a single strong hooked central it is stella de tacubaya, and if the radial spines are fine and overlapping, and the centrals slender and long, then is proper name is gasseriana. In both cases, the central spines are not always present.

Chris, your definition of M. gasseriana as having fine and overlapping radial spines and slender and long central spines, and M. stella-de-tacubaya as having clusters of radial spines and a strong hooked central spine, is quite appropriate in my opinion.
In Durango I have found only M. stella-de-tacubaya like plants, but sometimes the central spine is lacking. SB1161 and SB 447 are M. stella-de-tacubaya, but Steven Brack still lists them as M. gasseriana. This is because in the past, these plants were considered as being M. gasseriana (Helmut Rogozinski used to be a strong defender of this). I would say that all plants listed as M. gasseriana in the Mesa Garden catalogue, are actually M. stella-de-tacubaya.
In the border area of Durango, Coahuila and Zacatecas things become more complicated. On the south side of the Sierra Jimulco I found plants which may be related to M. gasseriana, but I am not sure about this. Rogozinski has described them as M. viescensis fa. diablensis. Plants from different nearby locations in this area sometimes look quite different from each other. About 25 km from here, just to the north of the Sierra Jimulco one can find M. lasiacantha on the hills south of Torreón. Then, 50 km to the northeast, in the Cerro Bola region, grows the real M. gasseriana.

As far as RS571 is concerned, for the moment I qualify it as M. magallanii var. hamatispina. I sent a few notes about it to Bill Maddams (will be qouted in the next JMS). To summarize: It is said to come from km 163 of MEX-40. This is about 25 km northeast of El Amparo where I found M. gasseriana at two locations. However, only 10 km east of RS 571 is a location of M. magallanii, namely ML 536 from microondas Santa Lucia, which Lacoste labelled M. magallanii var. hamatispina. On the internet I found two photos from Michel Lacoste of his ML 536. The plant on one photo looks very much like M. lasiacantha, the plant on the other photo has very pronounced and very long hooked centrals and it looks quite a lot like the RS 571 that i have in my greenhouse.

Wolter. M. chica, RS 414 is from Cerro Bola itself, then it is probably just M. lasiacantha (a very nice form though). At Cerro Bola I have not found any laf M. chica, RS 414 is from Cerro Bola itself, then it is probably just M. lasiacantha (a very nice form though). At Cerro Bola I have not found any lasiacanthaes with central spines. According to Helmut Rogozinski, the type locality for M. chica Reppenhagen is near Viesca. Based on field data obtained from Rogozinski, I did find the lasiacantha form at that type locality which had hooked (sometimes just slightly hooked) central spines on the young plants (WTH 710). About 30 km from there, southeast of Viesca, I also found a Mammillaria with (almost straight) central spines on young plants (WTH 322).
RS 571 is mentioned as being from km 163 of MEX-40. This is about 25 km east of Cerro Bola. Km 163 is fairly close to M. magallanii territory, the closest magallanii location being only 10 km away (ML 536 from microoondas Santa Lucia, labelled M. magallanii var. hamatispina by Michel Lacoste). Somewhat further to the east and southeast one can find more magallanii populations. Perhaps, RS 571 is somewhere in between M. magallanii and M. gasseriana (previously labelled M. viescensis; my nearest gasseriana location being about 25 km to the southwest, near El Amparo (WTH 548). Nevertheless, RS 571 is very interesting. I have one plant in my greenhouse and I still do not know where to place it, I will have to wait till it gets larger. On the internet I found two photos from Michel Lacoste of his ML 536, M. magallanii var. hamatispina. The plant on one photo looks very much like M. lasiacantha (no centrals visible), the plant on the other photo has very pronounced and very long hooked centrals and it looks quite a lot like the RS 571 that I have in my greenhouse. For the moment, M. magallanii var. hamatispina seems to be the best option.