When: 2017-11-16

Collection location: Monterey Co., California, USA [Click for map]

35.8356°N 120.354°W 415m [Click for map]

Who: J-Dar

Specimen available

On decorticated wood of Blue Oak (Quercus douglasii).

Thallus crustose, scant, mottled greyish brown, epruinose. Apothecia common, tiny, in contigous groupings or uncommonly single or in small groups, sessile, with a dark maroon disk becoming very dark in age, and persistent yellowish-tan thalline margin. Disk plane, at times convex, epruinose to rarely lightly pruinose. Margin entire, rarely flexuous to crenulate. Thallus and all parts of apothecia K-, C-, KC-. Exciple with algae. Amphithecial cortex thin, as seen cross-polarized. Amphithecium POL+ with yellow crystals, soluble in K. Hymenium orangish hyaline, hypothecium hyaline, epihymenium reddish brown, pigments soluble in K. Small crystals observed cross polarized are on top of epihymenium in a very thin layer on episamma, not down between paraphyses tips, soluble in K. A thin line of POL+ crystals is on top of algal layer below hypothecium.

Spores simple, hyaline, ellipsoid. Asci and spores found were immature.
Measurements in K of immature spores squashed out averaged 11.1×5.4 µm (n=4).


Apothecial section in water
Apothecial section in KOH
Cross Polarized
Detail of amphithecial crystals cross polarized.

Proposed Names

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Recognized by sight

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Add Comment
I’ll get back to this one in a year or two…
By: J-Dar
2017-11-19 22:41:55 SAST (+0200)

My eyes are crossed and my brain fuzzy!

McCune’s treatment
By: Jason Hollinger (jason)
2017-11-19 21:11:54 SAST (+0200)

Photos at: https://oregondigital.org/sets/lichens-pnw.

His key, abridged:

5a. cortex distinct and thickened to the base . . . 7
5b. cortex either distinct and uniformly thin or indistinct . . . 14

7a. spores narrow, averaging < 4.5 µm broad, Q > 2 . . . L. mughicola
7b. spores broader, averaging > 4.5µm broad, Q < 2 . . . L. coniferarum

14a. disk beige to light orangish brown, rarely with olive tints . . . L. albellula
14b. disk beige to more often brown, sometimes blackish . . . 15

15a. apothecial margin yellowish; disks yellowish, tan, to typically black or blackish green . . . L. mughicola
15b. apothecial margin pale greenish, greenish gray, tan or gray; disks pinkish to tan, reddish brown, or brown, rarely black . . . L. saligna

Note also that L. abellula and L. coniferarum are the only species in this group which contain usnic acid minor in addition to the usual isousnic major. But that’s not helpful without TLC.

Further notes:

L. saligna can often be recognized with a hand lens by the apothecial margin and thallus that are hardly yellowish at all and the apothecial margin that is usually persistently raised and often beaded.

L. albellula, though variable, the most typical appearance is a dense array of tiny brown apothecia with a disappearing margin.

L. coniferarum is distinguished from L. saligna by the basally thickened amphithecial cortex, broader spores and usually the presence of usnic acid.

L. mughicola – no comments, but note that other authors all agree on the dark apothecia. And the epihymenium is N+v where blackened, but the million-dollar question is whether all the species will be N+v in blackened apothecia? It’s possible that any will blacken where exposed to the sun, which is presumably what you are suspecting in your specimen.

Thallus (for what it’s worth!): L. saligna = usually poorly developed, variously sized granules to occasionally areolate; L. mughicola = indefinite to rimose to warty-areolate; L. albellula = barely apparent to warty-areolate; L. coniferarum = granular.

Just for the record – My eyes still cross every time I confront this group. :)

P.S. Spores:

length width source
L. albellula (7.0)8.0-12.5 (3.5)4.0-5.0(5.5) µm
L. coniferarum (9.0) 10-12.0(13) (4.0)5.0-6.0 µm
L. mughicola (7.0)8.5-11.9(14) (3.0)3.5-4.6(5.5) µm Printzen 2001
L. saligna (6.5)8.4-12.3(15) (3.0)3.4-4.7(5.5) µm Printzen 2001
Thanks Jason
By: J-Dar
2017-11-19 20:40:06 SAST (+0200)

I did consider L. mughicola, but couldn’t get it there in the keys, Ryan’s or Nash. I don’t have McCune’s though, available online? The dark apothecia seemed a minor part of the lighter grouping, and I did notice some parts of the keys talk about them darkening or blackening, but I figured this was minor overall. Where are McCune’s photos? Mughicola also seemed a bit out of range. I don’t have nitric acid, but maybe its time to find some!

Some of these apothecia are very dark
By: Jason Hollinger (jason)
2017-11-19 20:07:01 SAST (+0200)

Have you considered L. mughicola? Do you have concentrated nitric acid? (Mine keeps eating through bottles so I’m essentially out!) L. mughicola has an N+ red/violet epihymenium.

Do you have McCune’s new keys? Check out his treatment (very different approach to the Sonoran Flora’s), and more importantly, check out his photos on-line. He has several close-up photos of each of the saligna group species. Hardly clears up the tangle, but very interesting.