Observation 98789: Micarea Fr.
When: 2012-06-27
(47.4288° 117.5936° 701m)
Herbarium specimen reported

Notes: Substrate: underside of Ponderosa pine branch (~8cm diameter) leaning up against 50+year old Ponderosa pine.

Habitat: Ponderosa pine grove on edge of wetland. (southwestern edge of Upper Turnbull Slough). Nearby plants include shrubby Salix sp, sedges/rushes.

Description: Green crustose thallus (when both wet and dry), globular-areolate, goniocysts. Upper cortex very thin, thallus primarily composed of photoboint, at 5x white medulla is only seen in a few isolated pockets, Under LM, medulla is very thin in-between coccoid green algae.

Apothecia: black, pruinose, convex, from 0.5&mm – 1mm diameter. Seem to be lacking both a exciple and margin. Epihymenium staining purple in K, pink/violet in C. Asci club shaped, very thick tipped staining blue in IKI,

Ascospores: both one and two celled spores seen, long narrow ellipsoid, pointed ends often. (8-)10(-12)µm x 2-3(-4)µm (n=9).

Paraphysoids: appear to be present, appear to be non-septate, branching at ends.

Photobiont: chlorococcoid, about 5µm in diameter.

Pycnidia: totally immersed in thallus, ostiole difficult to see but appears to maybe be black, in cross section pycnidia hyaline. Pycnospores ellipsoid, some of them are K+brown, 5(-8)µm x (5(-8)µm. but this may be a parasite or simply contamination due to an unclean razor blade.

Brodo “Lichens of North America”
Bruce Ryan’s Preliminary Key to North American lichens


chem tests
IKI test
margin and exciple appear lacking
C+pink epihymenium
K test on photobiont – hard to tell if gel around photobiont turned violet, my notes say no, but thoe photograph suggests perhaps it has.
Pycnidia and possibly the pycnospores stained brown with K.

Proposed Names

-5% (2)
Used references: Bruce Ryan: Discolichen Key.
Based on microscopic features: Spores: narrow ellipsoid 2 celled, some 1-celled, both seen.
No exciple seen, no margin seen.
Asci tips thick, Basidia like.
Based on chemical features: Epihymenium: K+purple
Asci tips: IKI+blue, thick tips staining blue.
Thallus Medulla and Upper Cortex: K-, C-.
61% (2)
Used references: Bruce Ryan’s Key to Discolichens and Micarea.
A phylogenetic study of the Micarea prasina group by P. Czarnota (2010).

Please login to propose your own names and vote on existing names.

Eye3 = Observer’s choice
Eyes3 = Current consensus


Add Comment
C+ pink = gyrophoric acid
By: Jason Hollinger (jason)
2012-07-01 19:50:37 MDT (-0600)

(In other groups, bear in mind that erythrin, and lecanoric, olivetoric and alectorialic acids are also C+ red, but those are typically much stronger.)

The C+pink in the epihymenium
By: nastassja (Nastassja Noell)
2012-07-01 19:25:43 MDT (-0600)

that would mean gyrophoric acid, yes? Since C+red indicates gyrophoric acid?

This specimen’s epihymenium is C+pink. If that indicates the gyrophoric acid is then that throws out M. hyssacea. I’ll try pulling out the polarizing filters to see if gyrophoric acid lights up – yay!

Might come down to TLC to check for methoxymicareic acid (only in M. micrococcus, M. hyssacea), micareic (only M. prasina) and prasinic acids (only M. subviridescens) (Czarnota p. 8).

You’ve taken this as far as I can go
By: Jason Hollinger (jason)
2012-07-01 19:25:40 MDT (-0600)

This is all new territory for me.

By: nastassja (Nastassja Noell)
2012-07-01 18:53:37 MDT (-0600)

leaning towards Micarea. Bruce Ryan’s key pointed towards M. prasina and looking deeper into M. micrococca gets even better…

From Czarnota and Guzow-Krzeminska’s 2010 “A phylogenetic study of the Micarea prasina group shows that Micarea micrococca includes three distinct lineages” (The Lichenologist) I’m gathering the following information:

Micarea micrococca s. str. (Körb.) Gams ex Coppins: Apothecia: white, 0.1–0.3 mm diam. Hymenium and hypohymenium:K−, C−. does not have K+violet in epihymenium as does M. hyssacea (see pg. 13 and 16).
Pycnidia usually abundant, often embedded in between the goniocysts, bearing widely gaping ostioles or bearing white blobs of cylindrical mesoconidia (3·8–)
4·5–5·5 × 1·2–1·5 μm, or narrowly cylindrical or fusiform microconidia 5–7·5(–8) × 0·8–1 μm
Ascospores: oblong-ovoid, elipsoid, (0–)1-septate, 10–12(–16) × 3–4·5 μm. Chemistry: Thallus and apothecia K−, C−, Pd−. TLC: methoxymicareic acid.

Micarea byssacea (Th. Fr.) Czarnota, Guzow-Krzeminska & Coppins comb. nov.
Thallus: gel in between algae K+/- violet. Apothecia: olive-grey to blackish-grey, (0·1–)0·2–0·6 mm diam. Hymenium: K± violet, C± violet, because of ‘Sedifolia- grey’ pigment, confined to gel-matrix, epihymenium and gonidiocysts (see p.16). Spores: long,oblong-ovoid, ellipsoid, 0(–1)-septate, (6–)8–12(–13) × 2·7–3·5(–4·2) μm.
Pycnidia:sometimes present, white to grayish white, gaping ostioles, pycnidial walls around ostiolum K± violet, C± violet; spores same as M. micrococca.
Chemistry: Thallus and apothecia K−, C−, Pd−. TLC: methoxymicareic acid.
Substrate: grows mainly on the bark of trees.

Micarea prasina grows usually on soft lignum, presence of micareic acid.

Micarea levicula, M. pycnidiophora, and M. viridileprosa have thallus, apothecia or pycnidia C+R due to gyrophoric acid (p16).

Micarea xanthonica will react C+ orange due to xanthones.

Micarea stipitata similar to M. micrococca but has distinctly stalked

… based upon the K+violet epihymenium and the darker apothecia, I am leaning towards M. hyssacea. The substrate of M. prasina is shot on, however,

I place my bets on Micarea
By: Jason Hollinger (jason)
2012-07-01 01:36:06 MDT (-0600)

But I think you were already decided on that yourself, based on your emphasis of the lack of discernable exciple. You’ve done a great job with the ascus stains and documnenting the subtle K+ purplish epihymenium and inconsistently septate spores. Together these are highly suggestive of Micarea. I think the most likely candidates are M. micrococca and M. denigrata. Did you do a C test on the apothecia in section under the microscope? You might only get a faint C+ pink on the epihymenium. There’s a way to see gyrophoric acid crystals using polarized filters, but I haven’t worked out the proper technique yet. C. Björk assured me that you could reliably see crystals even when the concentration was too low to see with spot test. (Let me know if you try!)

Created: 2012-07-01 00:59:13 MDT (-0600)
Last modified: 2012-08-23 19:35:20 MDT (-0600)
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