Observation 200204: Parmotrema reticulatum (Taylor) M. Choisy

When: 2015-03-06

Collection location: Southwest St. Louis Co., Missouri, USA [Click for map]

Who: weed lady (Sylvia )

No specimen available

There could be other lichen in this photo – like the upper right-hand corner. But the main body of lichen is my observation. Have seen other somewhat other similar observations using this genus. On a maple.



Proposed Names

28% (1)
Recognized by sight
84% (1)
Recognized by sight: can clearly see the reticulate marks on the upper surface at full-resolution => Rimelia group; soredia further restrict to P. reticulatum (extremely common) or one of its rare chemotypes

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Eye3 = Observer’s choice
Eyes3 = Current consensus


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Happy to help
By: Jason Hollinger (jason)
2015-03-08 14:24:00 CDT (-0400)

As you figured out I’m sure, the soredia are the powdery granules aggregated into little piles (called “soralia”), mostly along the ruffled margins in this species. The black hairs are called “rhizines” (think latin for “little root”). The Parmotrema often have them projecting out from the edge like this one (sometimes even more conspicuous) — these marginal hairs can be called “cilia”. It is always a good idea to note the presence of both the soralia and the rhizines, their shape and where they are found. Make a habit of turning lichens over — pry up an lobe tip or margin with a pocket knife and look for rhizines with a hand lens. Some are short stout little roots, others are forked like miniature trees, others are all bristly like bottle brushes. Lichens can be strikingly intricate and beautiful at 10x, a whole new world!

By: weed lady (Sylvia )
2015-03-08 11:20:13 CDT (-0400)

THANKS so much for the information. I know nothing (yet) about lichen, so anything you relate to me is valuable information. Think I understand now what the soredia is. But what would you call the black, hair-like projections? They are also visible on the underside. I have a sample of this lichen and am viewing it with a 10x lens. Thanks again for your help!

Created: 2015-03-07 07:49:11 CST (-0500)
Last modified: 2015-03-07 14:31:05 CST (-0500)
Viewed: 65 times, last viewed: 2017-06-19 23:50:52 CDT (-0400)
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