What are the EXACT defining characteristics of the 2 species. Rib counts, shapes vary greatly. Flower colour can go either way. Pollen is said to be too variable. Skin colour varies as well. Is cell structure different? I can’t find any info leading to macroscopic identification. Lots of guess work but I see no evidence of true specie differentiation. One possibility is location, but this seems grossly inaccurate. God knows how many different ways seeds can spread. I don’t own Andersons (Peyote, the divine cactus) book but I have read it and he gives very little info as to true identification. Any thoughts?
naturally-growing (non grafted) specimines differ alot at maturity. diffusa tends to be lighter colored and rounder. flowers are most likely white. if you have 2 to compare, the difference is more noticable. both species are higy variable tho. they say that williamsii self polinates but diffusa doesnt. but they "say" alot of things. :)
ahh you are over here as well :) well if no body knows why are we even saying there are 2 species? i really cannot accept that no one knows of any real differences. should there only be one lophophora species, and perhaps subspecies/varieties?
oh, you were you, were you? :) nope, these far more likely are 2 distinct species. comparitively, williamsii can grow the ribs in well-defined lines, diffusa appear more wavy, and the ribs are less pronounced especially when older. do a little google image searching on both, youll see that diffusa occurr regularly with distinct visable traits that set them apart from williamsii characteristics. cant think of any better way, you really have to SEE the differences, its not enough to just be told jourdadia (or whatever) on the other hand.. try defining that
but that one is apperantly a hybrid of something, people say anyway. i have googled till the sun rose and i still say that either people are mislabeling, incorrectly id'ing or the specie definition goes further. yes the ribs are often as you describe them, but then other places say that "this photo" is X specie and it looks completely different. i too am inclined to go by the common ids of rib formation and colour, but i do not see that as a 100% id by any means. judging by the internets lack of scientific evidence i am starting to think they may be better placed as a subspecies. That and people of apperant authority give the impression lophophora can be very variable. frankly, to me, its like comparing asians to africans. i am very interested to know what anderson and others that studied these cacti say. they wouldn't have actually made a whole new specie for just for rib differences that are often variable, would they? i guess the other problem i seem to overlook is most photos are of cultivated specimens and could have easily been hybridized and therefor variable.
i just realised that this place has a taxonomy forum! i should have put it there so i will make a new thread and continue discussion there.
Yes, I'd hit books as more reputable sources of information than what you'll find online. It is quite possible for two species to have characters that overlap in many properties. The Wikipedia article does cite a DNA study that reinforces the notion they are separate species.
In The Cactus Family, Edward F. Anderson describes the two species of Lophophora. In L. diffusa the ribs are usually absent, in williamsii they are usually present and well defined. Usually is a problem for people who want definite traits to distinguish their plants. The most definite distinction between the two that I see in the descriptions is that diffusa is described as, "Stems soft, somewhat globose, yellow-green ..." and williamsii is described as, "Stems globose to flattened globose, somewhat firm to the touch, blue-green or occasionally reddish green..." The colour in the two photos Anderson publishes is very distinctly different, diffusa quite yellowish and williamsii quite blueish.
yes there are a few "usuallies", if that is a word, but that is not an "is". andersons other book "Peyote: the divine cactus" also has a chapter on this, but i find it less that certain. i have a good understanding of what people consider to be a diffusa or williamsii, but look at the varieties and the variable everythings. there are diffusa with pink flwers, ribs that fly out everywhere in both sp. colours that don't match. i would trust a dna test, but i have not read that book yet (now i must i think). What would you peg this one as? it has pink flowers, like williamsii usually does, but it is yellow-green like diffusa is usually. the ribs to me look a little williamsii like but htey are rather irregular, perhaps unusual. these are mine, a google search will yeild far more "unusual" specimens :) http://img.photobucket.com/albums/v486/kadakuda/lophflower11.jpg http://img.photobucket.com/albums/v486/kadakuda/loph3.jpg photo of the anther, but its not close enough to show anything. and the pollen is apperantly to variable to be worth the effort. http://img.photobucket.com/albums/v486/kadakuda/lophflower10.jpg http://img.photobucket.com/albums/v486/kadakuda/lophflower2.jpg here is a copy of the book chapter. it is available on many websites. my eye opener is this one: "Normally the epidermis is covered by both cuticle and wax; the latter substance is primarily responsible for the blue-green or glaucous coloration of L. williamsii." but if williamsii can be yellow/green does this throw that oen out the window? i have yet to take a slice off my cacti and look under the scope, i will do so when i have a so called diffusa to compare. http://www.erowid.org/plants/peyote/peyote_info1.shtml#index-4
you still trying to ID those hylocereus-grtafted lophos? :) you know, grafted specimines do not follow conventional growth patterns at all anyway. you're probably going to have to settle on something like "diffusaform Lophophopra williamsii" as your specimines match the suggested morphological guidelines for diffusa, AND the color scheme and self-pollinating habits of williamsii. you really cant rule out the product of rampant unchecked hybridization in whatever "research-grade controlled" asian facility those grafts were mass-produced in :) i think youre letting this get to you too much :) I dont think you CAN positively ID them.
haha fair enough. but other people have shown photos of similar unknowns that are labelled either way. my cacti aside, i still think there is more to flower colour and skin colour/formation. i guess many could very well be hybridized, so perhaps seeing wild photos is best. in all the information out there, are these main charectaristics the defining points of these guys? seems rather grey.
indeed. i hav ebasically given up onthsoe 2 grafts. i will return in 5 years with a bunch more to annoy everyone with questions. i do find humans understanding a little more grey than nature though. if 2 species cannot be defined clearly, why are they 2 species?
Well, as to what is a species depends on your definition of species (unfortunately). For a bit of light reading, check out Wikipedia's article on [WIKI]species[/WIKI]. The other thing to do that might prove enlightening is to read the original descriptions of each species, wherever they were published. For Lophophora diffusa, the description should be in Cact. & Suc. Mexic. xii. 13 (1967) while Lophophora williamsii was published in Contrib. U.S. Nat Herb. iii. (1894) 131
well i used to go by morphological and sexual characteristics for a specie definition. but this cactus can be hybridized with others and have fertile young, so that’s ruled out. I think morphologically these are rather variable. I cannot find any, free, info on those books you mentioned, so I will have to wait and see. Perhaps the libraries can get them here, but I doubt it being in Taiwan. Most things I have found are talking about differentiating Lophophora from other genera and not so much about what species should be included within the Lophophora genus. I guess I need to buy that book though :) In Andersons book these points stood out to me. “Normally the epidermis is covered by both cuticle and wax; the latter substance is primarily responsible for the blue-green or glaucous coloration of L. williamsii.” But this section makes no mention of L. diffusa. “The flower color of Lophophora varies from deep reddish-pink to nearly pure white; those of L. diffusa rarely exhibit any red pigmentation, making them usually appear white or sometimes a light yellow because of the reflection of yellow pollen from the center of the flower.” But even Anderson uses the word rarely, as in there still is pink diffusa. To me it can be used as a clue, but not as a specie description. “Lophophora seems to stand by itself in possessing a particular combination of morphological characters unlike any other group of cacti. Its nearest relatives appear to be the genera Echinocactus, Obregonia, Pelecyphora, Ariocarpus, and Thelocactus. The character of seeds, seedlings, areoles, and fruits certainly support the contention that peyote belongs in the subtribe Echinocactanae (sensu Britton and Rose) rather than in the more recently proposed "Strombocactus" line of Buxbaum. Perhaps the poorly understood genus Thelocactus may be the single most closely related group.[30]” Lastly this one. This makes me think that they based it on morphology more than anything. I do not know much about cacti but from m reading the last while I am getting the feeling that taxonomy is not where it should be in this family. Anyone happen to know what the species descriptions are from the original collectors? Thanks for the discussion :)
The taxonomy of the Cactaceae has changed multiple times. If you look at some species, they have a dozen synonyms - a good indication of taxonomic confusion.
