Notes: On Si rock (conglomerate) in open coniferous forest. Very common east side Cascades according to McCune – Miscellaneous Keys to Microlichens of the Pacific Northwest of North America.
Interesting that different references vary in almost every detail. E.g. Owe-Larsson has thallus “gray to white-gray or almost white, sometimes with a yellowish tinge” while Thompson has it as “ashy gray, but sometimes stained rusty” and Brodo has “very pale to rather dark greenish-gray or chalky white” ; Smith et al. has “prothallus black, delimiting” while Owe-Larsson has it “often absent, when present found in parts along the thallus edge as a narrow dark zone, rarely fimbriate, black to blue-black or brown-black”; etc.
Brodo says "In North America, several species that contain norstictic acid but differ in thallus color and development as well as substrate type can be found in museums filed under “A. cinerea,”" Smith et al. says “Because of variations in colour and roughness of the areoles it is likely that several described species are included here.” Thompson says “There may be several entities within this broad concept of the species…”
With respect to thallus thickness and texture which are considered important in determination of species, those characteristics vary abruptly and considerably within some of my specimens.
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Bruce Ryan, that is. Something along the lines of it be the absolutely worst genus he’d ever had the misfortune to study. :)
Owe-Larsson et al. 2007 in Sonoran Flora rely heavily on combo of ascospore and conidia size, chemistry, number of swollen apical cells on paraphyses to delimit species. I don’t believe this concept has been applied to northern species(?) It would seem that this would be an important first step. but ultimately I think molecular evidence will have to be brought to bear to either support or dismiss these new species concepts.
With respect to Aspicilia I recall Bruce McCune wondering whether Aspicilia had a great many very similar species or only a few highly plastic species.
It would be interesting to see spore and conidia size size for these specimens, too. I wonder if it would be possible to separate this complex into species based on those characters? Thallus color and texture, based on my growing experience from southern California, is a remarkably poor character to use for taxonomy in Aspicilia.
Created: 2013-03-10 03:28:31 CET (+0100)
Last modified: 2013-03-10 03:28:35 CET (+0100)
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