When Can A Picture Be Trusted? by Harry E. Luther in J.Brom Soc. 45: 117. 1995
A recent comparison of Dyckia marnier-lapostollei with Dyckia cinerea made me think at first that it was a valid attempt based on the published work of authorities, but then I did a little research that I shall describe.
The problems associated with cultivated Dyckia marnier-lapostollei and D. cinerea result from the condition that they are probably the same thing. Note that I say "cultivated." This is a horticultural identification problem and not a taxonomic problem in the strict sense.
Real Dyckia cinerea is probably not in cultivation, at least in the United States, unless it has very recently come in as wild collections from Caraga or vicinity. I have not seen any. I have a photograph of the type specimen of D. cinerea (Glaziou 18570 at Berlin) that portrays a plant very different from D. marnier-lapostollei. The leaves are much longer, relatively narrower with much more laxly arranged, generally shorter spines. The scape is very much more robust; the inflorescence appears more densely flowered than any D. marnierlapostollei. The specimen is only a fragment but I suspect that the overall appearance of this species is quite different from D. marnier-lapostollei as well.
So what's the problem? Why any confusion? To find out, look at the black and white photo in Dr. Werner Rauh's BROMELIADS, the 1979 English edition, or in the later, reprinted edition BROMELIAD LEXICON, between pages 290-291, illustration 252. See the Dyckia cinerea? Get our your pencil. It's really a Dyckia marnier-lapostollei. The identification was corrected in the later German edition of BROMELIEN but not brought to the attention of English-only readers.
If there are any questions about "big" Dyckia marnier-lapostollei, consider the culture involved. The type specimen, which can be seen in the photos in the protologue, appears to be in a very small, perhaps four-inch pot. Most of us now grow these things with much more root room. Was the type specimen "bonsaied"? Are our robust specimens normal? Eight or so years ago, I saw a few freshly collected plants that were at least 50% larger than what was reported in the literature. I'm sure that size can vary somewhat so this characteristic should not be cause for undue suspicion.
If any one has living material that he or she is sure is Dyckia cinerea let me know. I will be glad to try to verify it. —SeeSmith & Downs 1974
