Observation 161444: Rhizocarpon Ramond ex DC.

When: 2014-03-03

Collection location: Serra de São Mamede, Portugal [Click for map]

Who: zaca

No specimen available

These two specimens live on the same fence that the lichens in observation 161352 and observation 161353. I think that they belong to the genus Acarospora and appear to be in different stages of the development of the thalli, the first one with flat and the second with convex areolas, though both are fertile. The apothecia seem to be a bit to big for A. socialis or for A. schleicheri, the yellow Acarospora spp. I know, but none of these species can be excluded.
After the microscopy, it is clear that Acarospora is ruled out, and it is now clear that it is a Rhizocarpon. Which one?
The spores are muriform, with up to ten cells, two or three transverse septa and one longitudinal septum, with the following average dimensions:
Me = 35 × 16 um ; Qe = 2.2 (N=26).
As usual in this genus, they are light colored when young and became darker at maturity.


Miscellanea from microscopy.

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Old donkey doesn’t learn new languages!
By: zaca
2014-04-01 13:35:38 PDT (-0700)

This is a portuguese dictate, as an answer to your sugestion of learning Swedish.
Concerning the colours of the specimens: I would say “yellowish” with no shade of brown. In fact, the lowest part of both specimens is yellow and, going up, the colour becomes lighther, almost durty white at some places. Maybe, it was these combinations that lent me to Acarospora at first.

Is this yellow?
By: Jason Hollinger (jason)
2014-04-01 12:39:29 PDT (-0700)

Sorry, I’m working in poor lighting conditions, and I genuinely can’t tell if this is brownish or sun-bleached yellow! Either way, I can send you pdf scans of treatments which might help: Runemark did a treatment of yellow species of Europe several decades ago. And the Swedish Flora has a good treatment from ~10-15 years ago of all the Scandanavian species; one might be a good match. (You’ll need to learn Swedish, though, haha!)

Created: 2014-03-15 11:19:33 PDT (-0700)
Last modified: 2014-03-20 03:59:35 PDT (-0700)
Viewed: 45 times, last viewed: 2018-06-15 23:46:23 PDT (-0700)
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