Observation 109526: Opegrapha Ach.

When: 2012-09-12

Collection location: Hug Point State Park, Clatsop Co., Oregon, USA [Click for map]

Who: Richard Droker (wanderflechten)

Specimen available

can hardly believe how much time spent (and could spend considerably more, e.g. chemistry, ink mount) on this tiny (2×1cm) specimen

on “carbonate cemented feldspathic and lithic sandstone” of middle Miocene Astoria Formation, well above high tide, not shaded

lirellae to 2.0 × 0.6 mm

growing with or over a Verrucaria sp.

O. herbarium and O. rupestris 3-septate spores:

O. herbarium Smith et al. (2009) has spores (16)18-24(-26)u with “distinct perspore”, on “…bark, wood… and sandstone, often in shaded situations”;McCune has spores 18-22×5-8u, “fairly common on Picea and Pinus twigs, also on hardwoods and other substrates”; Ertz and Egea has spores 18-28x(4-)5-8u, “on acid to basic bark or on rock… when on rock, in ombrophobous [shielded from rain] communities…”

O. rupestris – compare with photo by Curtis Björk at http://www.waysofenlichenment.net/lichens/Opegrapha/ ; Smith et al. (2009) has spores 14-22×5-8u, lichenicolous “On crustose Verrucariaceae, especially V. baldness, on hard limestone”; in the key of Brodo (2001) “on calcareous rock. Spores 4-celled, 22-29×5.5-8u; thallus thin or endolithic, often parasitic on other lichens”; Thompson (1997) has O. saxicola (= O. rupestris on North American Checklist) spores 20-30×5-8u without perispore, “on the underhangs of calcareous rock cliffs”; North American Checklist has it as lichenicolous

McC “Opergrapha is understudied in the PNW. I suspect the number of species could easily double by focusing on the genus.”

Ertz and Egea “This is a large and difficult genus, especially for the corticolous and lignicolous species with a lot of contradictions in the literature, and some unsolved problems.” (my underline)


Proposed Names

83% (1)
Used references: Smith, C.W., Aptroot, A., Coppins, B.J., Fletcher, A., Gilbert, O.L., James, P.W. and Wolseley, P.A. (2009) The Lichens of Great Britain and Ireland; Opegrpha (revised 2004) In Bruce McCune’s Miscellaneous Keys to Microlichens of the Pacific Northwest of North America; Ertz, D. and Egea J.M. in Nash III, T.H., Gries, C. and Bungartzk, F. (ads) (2007) Lichen Flora of the Greater Sonoran Desert Region, Volume 3; Brodo, Irwin M., Sharnoff, Sylvia Duran and Sharnoff, Stephen (2001) Lichens of North America; Thomson, J.W. (1997) American Arctic Lichens, 2. The Microlichens
Based on microscopic features: hymenium 75u high; paraphysoids appear to anastomose; spores 8/ascus, 3-septate, average 28×10u

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= Observer’s choice
= Current consensus


Add Comment
Good grief!
By: Jason Hollinger (jason)
2012-09-13 02:50:49 CDT (-0400)

“ombrophobous”? Who talks like that! :) You’ve got to love the difference in spore size between the British Flora and North American authors.

But I’m not seeing anything resembling a perispore here. Do you maintain doubts? It would seem that O. rupestris is the best name for this based on all the info you’ve given.

What a lot of work. Was it edifying? :)