Notes: on Sambucus racemosa branch 1.5cm diameter which extended out over sandy beach (salt water)
20cm or so of this branch which I collected has 8 or more lichen species, including observation 93436 (Jason – sorry, I forgot how to refer to observations) and some others worth posting
Interesting remark by Harris – “Being unable to recognize two genera at this time, I have decided to accept the decision of the North European lichen oligarchs to force their will on the rest of the world and conserve Anisomeridium. (There are only three species in North Europe but 100+ in the rest of the world.”
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Since your comment I’ve looked hard for clearly branching paraphyses in several species, and realize that is more difficult to find than I have previously thought. I did see some in a Rhizocarpon for which I’ll post images.
re: branching interascal filaments
Even just knowing that it takes practice and patience and twiddling of knobs to see helps a great deal. If it’s that difficult to see, I’m bound to wonder if maybe I’m trying to hard to see what’s not there, and that some day when I finally see true anastomosing filaments it will be like a 2×4 upside the head. :) What I hear from you is: it’s not obvious.
Practice, practice, practice… Eventually some day I should gather a few specimens whose ID I’m positive of, and check the differences between species which definitely have anastomosing paraphyses, and others which definitely don’t. Make a real study of it. Same with ascus type, Physciaceae spore type, inspersed hymenium, etc.! Lots of microscopic characters still elude me. :)
As always, your comments are greatly appreciated.
Another word for this identification might be provisional. Its the best I can do, at least for now, or until an expert weighs in.
Details of interascal filaments* do not show in the posted photo. Through the scope at 1000x (with lots of little focus adjustments following vertical position of hyphae) branching does show clearly. (I have often been frustrated with this but it has become easier. You probably have experienced the variations of lighting (e.g. diaphragm opening, etc.), thickness of section and amount of pressure on coverslip (I usually bounce a pencil with eraser down), how long the preparation sits around (often improves with time), etc. in helping to see these things.
*A useful term. Another new one for me was clypeate. Smith et. al’s glossary has clypeus – “stromatic growth, comprising fungal hyphae and bark tissue” as with the involucrellum of Arthopyrenia. There is a more complete definition in Nash III et. al Sonoran V3 p. 35.
Wow, yes, these genera are even more confusing than I thought. I didn’t realize how subtly Strigula differs from Anisomeridium (ascus structure and conidia). I think “no good matches in Strigula” is a perfectly good reason to go with Anisomeridium. :)
re: branching interascal filaments
Can you see them in your photo? I have a great deal of trouble diagnosing this character (and equivalent for paraphyses in apothecia)
Regardless, you have me convinced. Just trying to learn…
I posted this with the identification as “promising” but perhaps “could be” is better. Your question forced me to look at it again. (It may be that for me to be be confident with this specimen would require my becoming considerably more familiar with a number of these genera. Don’t know if I have the time and energy for that right now.) Sorry – thought I had mentioned the photobiont is trentepohliate. Also potentially useful info: the interascal filaments are somewhat branched, the asci are uniseriate (in some the spores are en echelon), obviously the cells within spores are of unequal size, the perispore appears to be without ornamentation (in H2O and KOH), the involucrellum does not appear to contain wood cells (in places I’m not sure what I’m seeing). The key in Smith et. al makes use of ascus structure, with a narrow ocular chambering ascus apex (fig. 10b) for Strigula, an indistinct or short and broad ocular chamber (fig. 10c) for Anisomeridium, and an apical dome with a broad ocular chamber surmounted by a hemispherical meniscus-like structure (fig. 11a – may requite congo red stain to see this) for Acrocordia. One of my images shows ascus structure fairly well, but I am not able to choose between the options offered in Smith. Can’t find any species of Strigula that fits. Arthopyrenia is described as having a clypeate involucrellum, although I’m concerned that I’m not seeing wood cells which may be present. Acrocordia should have a verrucose perspore. Some other genera seemed even less likely. All in all I’d still call A. biforme promising, but I’d gladly defer to a more expert opinion.
How are you ruling out other similar genera like Strigula and Arthopyrenia? Are they simply not present in the northwest? Isn’t it important to check for Trentepohlia in these sorts of peritheciate crusts? Some aren’t even lichenized, right?
I’d never noticed Harris’s remark. It helps explain some things…
Created: 2012-04-30 14:08:20 EDT (-0400)
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