Observation 59335: Lichen P. Micheli
When: 2010-11-07
No herbarium specimen
0 Sequences

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By: Jason Hollinger (jason)
2010-11-24 08:29:02 CST (-0500)

What you’re seeing here are half-buried spherical perithecia. You can see the wall (“exciple”) and gaping pores into the hollow interior (initially filled with asci and spores and paraphyses (periphyses? paraphysoids? long narrow sterile hyphae, whatever they’re called in perithecia) and goo). In this case, the perithecia are covered with a white pruina; they are nicely exposed by the receding thallus — generally all you can see is tiny black dots, and occasionally lumps from the perithecia deforming the cortex. You definitely need to do a microscopic section of these to get anywhere. Chemistry will probably also be important. In addition to spore number, size, shape, color, number of cells, you will need to know details of the exciple — is it blackened all the way around, or only on the top; are there multiple layers in places, esp. around the apical pore; is the algae inside the cavity?; does the “goo” stain dark blue in iodine solution (lichenologists generally use Lugol’s solution or IKI). And so on. Oh, and for tropical crusts, it’s often important to distinguish those species whose alga is a Trentepohlia species from those with various other algae, such as the more common “trebouxioid” genera. (Trentepohlia forms long narrow branching strands of cells, trebouxioid genera are all unicellular, just round green balls.)

Created: 2010-11-20 12:23:03 CST (-0500)
Last modified: 2010-11-23 23:46:22 CST (-0500)
Viewed: 55 times, last viewed: 2017-06-30 12:46:31 CDT (-0400)
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