Observation 88545: Rhizoplaca subdiscrepans (Nyl.) R. Sant.
When: 2011-06-19
Herbarium specimen reported

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Thanks Chris
By: Jason Hollinger (jason)
2012-03-04 15:20:32 CST (-0500)

I didn’t know what “pulvinate” meant. I was just hoping no one would ask. :)

squamulose, pulvinate, rosulate
By: Chris Parrish (kitparrish)
2012-03-04 15:14:18 CST (-0500)

Bruce Ryan would be one of the first to help us with technical lingo. The following are from his glossary:

PULVINATE cushionlike; growing in small cushions.

ROSULATE in a rosette; a more restricted definition is given by Poelt (1958)

SQUAMULE a small (to 5 mm long and wide, or larger in basal squamules of Cladonia), complanate, scalelike thallus or thallus segment (lobe, foliole), usually more or less isodiametric (or at least short), with an entire to flexuous or crenate margin, with or without a lower cortex; intermediate between crustose and foliose, usually more leaflike than an areole (i.e., with a distinct lower side, often partly ascending or lifted off the substrate, sometimes removable intact). Many authors (e.g., Hale, Purvis, et al., Rogers, Taylor) restrict the term to structures lacking a lower cortex and rhizines; others (Galloway) describe a squamule as usually being corticate on both sides. Squamules usually lack a distinct stipe or umbilicus, but there is a continuum from peltate or stipitate areoles to umbilicate or subfruticose thalli.

SQUAMULOSE growth form composed of squamules; frequently forming extensive mats; also used interchangably with squamulate.

Oh brother!
By: Jason Hollinger (jason)
2012-03-04 15:09:01 CST (-0500)

Check out the top photo here:

http://opinicon.wordpress.com/...

Tell me if you can tell the difference between A and B! :)

Come on, I can’t be wrong all the time! :)
By: Jason Hollinger (jason)
2012-03-04 15:05:12 CST (-0500)

Yes observation 88528 seems particularly remarkable. Great list of names. Are L. muralis and L. valesiaca the only placodioid saxicolous species? No, there’s one more: L. opiniconensis.

This group was one of Bruce Ryan’s specialties, so his placodioid Lecanora file is voluminous. What a complicated group! If we accept for the moment that these are the only three species present in Wisconsin, we can say some useful things.

L. valesiaca – strongly pruinose
L. muralis – not at all pruinose, medulla solid but relatively loose and cottony
L. opiniconensis – … not sure… member of the L. crustacea group, apparently very frequently associated with (and confused with?) R. subdiscrepans

Here’s what Ryan says about this group:

The members of the L. crustacea complex, known especially from arctic to boreal areas, but spreading southward at higher elevations, have greenish yellow squamulose to pulvinate or rosulate thalli that are often divided into secondary areoles… This complex can often be recognized by the frequently olivaceous tinge of the thallus, which often turns orangish towards the lobe tips. These taxa also share a very peculiar and unexplained tendency for almost constant association (in both Asia and North America) with… R. subdiscrepans, a very problematic taxon, but one which is well distinguished from the L. crustacea complex by its pruinose discs, matt upper surface with a more grayish green color (without yellowish and orangish tints), looser medulla…

I’d say we definitely need to get a better grip on this mysterious L. opiniconensis!

Grudgingly agree:-)
By: Andrew Khitsun (Andrew)
2012-03-04 09:56:34 CST (-0500)

My misidentification comes from the fact that I’ve never seen R.chrysoleuca, I guess (except in pictures). Speaking of different color thallii, you’re probably referring to my observation 88528 and observation 88530. The latter’s specimen were actually deposited at UW-Madison with Jim Bennett. I took samples of both white and tan thallii (thinking it was two different species, or intergrade), and those weird “cabbage”-like structures. His verdict was that all of the material was R.subdiscrepans. He has visited the Observatory Hill State Natural Area himself last season too (that’s where observation 88530 comes from), finding only R.subdiscrepans. It’s very common in the area here. On the other hand, J.Bennett says R.chrysoleuca is very rare.
As far as this observation goes, I marked it as having been picked as a specimen. It must be with the rest of specimen J.Bennett has – I expect his IDs sometimes this spring.
Thinking of Lecanora, what do you have in mind? Here is a list of the genus in the area, per J.Bennett (The saxicolous ones are linked):

Lecanora albella (Pers.) Ach. Thomson 2003
Lecanora albellula Nyl. Thomson 2003
Lecanora allophana Nyl. Thomson 2003
Lecanora argentata (Ach.) Malme Thomson 2003
Lecanora argentea Oksner & Volkova Bennett 2006
Lecanora cadubriae (A. Massal.) Hedl. Bennett 2006
Lecanora caesiorubella Ach. Thomson 2003
Lecanora carpinea (L.) Vainio Thomson 2003
Lecanora cateilea (Ach.) A. Massal. Bennett 2006
Lecanora cenisia Ach. Thomson 2003
Lecanora chlarotera Nyl. Thomson 2003
Lecanora circumborealis Brodo & Vitik. Thomson 2003
Lecanora crenulata Hook. Thomson 2003
Lecanora dispersa (Pers. ) Sommerf. Thomson 2003
Lecanora expallens Ach. Bennett 2006
Lecanora fugiens Nyl. Sliwa 2007
Lecanora fuscescens (Sommerf.) Nyl. Thomson 2003
Lecanora glabrata (Ach.) Malme Thomson 2003
Lecanora hagenii (Ach.) Ach. Thomson 2003
Lecanora hybocarpa (Tuck.) Brodo Thomson 2003
Lecanora hypoptoides (Nyl.) Nyl. Thomson 2003
Lecanora impudens Degel. Thomson 2003
Lecanora intricata (Ach.) Ach. Thomson 2003
Lecanora invadens Magn. Bennett 2006
Lecanora iowensis Fink Thomson 2003
Lecanora meridionalis H. Magn. Lay 2004
Lecanora muralis (Schreber) Rabenh. Thomson 2003
Lecanora opiniconensis Brodo Thomson 2003
Lecanora perplexa Brodo Thomson 2003
Lecanora polytropa (Hoffm.) Rabenh. Thomson 2003
Lecanora pulicaris (Pers.) Ach. Thomson 2003
Lecanora rugosella Zahlbr. Thomson 2003
Lecanora saligna (Schrader) Zahlbr. Thomson 2003
Lecanora sambuci (Pers.) Nyl. Lay 2004
Lecanora semipallida H. Magn. Sliwa 2007
Lecanora subimmergens Vainio Thomson 2003
Lecanora subintricata (Nyl.) Th. Fr. Thomson 2003
Lecanora subrugosa Nyl. Thomson 2003
Lecanora symmicta (Ach.) Ach. Thomson 2003
Lecanora thysanophora Harris Thomson 2003
Lecanora valesiaca (Müll. Arg.) Stizenb. Thomson 2003
Lecanora varia (Hoffm.) Ach. Thomson 2003
Lecanora wisconsinensis H. Magn.

Too crustose
By: Jason Hollinger (jason)
2012-03-04 02:27:49 CST (-0500)

Note the detached areoles surrounding the thallus. This is truly crustose. R. chrysoleuca is all a single piece, attached at a single hold fast underneath. You can pop ’em off with a pocket knife pretty easily, just like Umbilicaria.

There seems to be a lot of variation in color in this set of observations. One, in particular, showed light and dark thalli growing side-by-side. I’m wondering if some of these might be Lecanora instead of R. subdiscrepans. I can’t even remember how to distinguish the two now that I think of it…

Created: 2012-03-03 22:54:23 CST (-0500)
Last modified: 2012-03-04 02:28:15 CST (-0500)
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