PB's flower pics '09 update 8/26

[peterb]

I'd like to see DNA data comparing "Hamatocactus" with it's possible closest Ferocactus relatives. Off the top of my head I can't even really pull up a picture of a close Fero. Thelos, yes.

peterb

[vlani]

How about Leuchtenderga for a close Fero?

[peterb]

hey that's an interesting one that I forgot. It is true that Hamatocactus and Leuchtenbergia seem to have some similar morphology, especially the long very flexible spines and pronounced tubercles.

peterb

[iann]

I'm not aware of any DNA studies that have included the main Hamatocactus species T. setispinus and F. hamatacanthus. It's perhaps worth mentioning that Hamatocactus bicolor and Hamatocactus uncinatus have also been named in the past, but are now more firmly placed elsewhere.

There have been DNA studies on a number of other Ferocactus, Thelocactus, Glandulicactus, and Leuchtenbergia species, and E. grusonii which I'll come to later. All these genera appear to be closely related and possibly even mixed. Certainly Leuchtenbergia and Ferocactus are difficult to separate by any criteria other than the bizarre long tubercles. At that level, it would be surprising if Hamatocactus isn't just as closely related and in the mix.

E. grusonii shows up firmly as a Ferocactus in a variety of DNA tests, but is thought to have a hybrid origin producing the non-Ferocactus flowers and fruit. I think the tests pick up the maternal line very strongly, but I might have that backwards.

[peterb]

I guess I'm always wanting a finer degree of distinction in what's related and how closely. I know the entire bunch is related, I'd just like to retain some of the names that recognize the differences more. "Hamatocactus" seems useful to me, maybe not taxonomically but as a way to refer to a couple of distinct-enough plants. When I visited with H. hamatacanthus in Texas it was striking how different the plants seem in habit and habitat from Ferocactus.

peterb