Observation 97763: Collemopsidium Nyl.
When: 2012-06-19
Herbarium specimen reported

Notes: Superficial on intertidal Si rock with barnacles. (Sometimes grows up onto the barnacles from the rock.) Of the 3 marine Collemopsidium species on the North American checklist (also considering the species in Smith et al.) the most possible would be C. halodytes, but this seems very distinctive. No photos which I can find online resemble this.

I would appreciate suggestions on this one.

Images

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Indicated is the perithecium whose section is seen in the following photo. There are very few of these volcano shaped perithecia on the specimen. The numerous pycnidia are smaller and constricted at base.
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As there are so few perithecia on the specimen I was careful to make a good section. Its a bit thick, but thinner slices fell to pieces.
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note paraphyses
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ascus
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section of thallus
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These were almost impossible to section. The interior of the larger ones didn’t have much discernible structure. Smaller ones were packed with hyphae, and seemed to be producing pycnospores (see following photo), but these were extremely variable, so I’m not sure.
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close view portion of ostiole of “pycnidium”

Proposed Names

28% (1)
Eye3 Eyes3
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; Grube, M. and Ryan, B.D. in Nash III, T.H., Ryan, B.D.,Gries, C. and Bungartz, F. (eds.) (2002) Lichen Flora of the Greater Sonoran Desert Region, Volume 1; (need to look at Mohr, F., S. Ekman, & E. Heegaard. 2004. Evolution and taxonomy of the marine Collemopsidium species (lichenized Ascomycota) in north-west Eruope. Mycological Research 108(5): 515-532)
Based on microscopic features: thallus up to 0.4mm thick with “hills and valleys” and grazed upon in places, average photobiont cells ca. 15×10u (quite variable), color cyanobacteria-like rather than green algae-like, arranged in columns; few perithecia (note involucrellum, paraphyses, etc in photo) 370u diameter; spores 1-septate, ca. 15×6u, appear to be up to 8 per ascus; very many pycnidia(?), constricted at base and smaller than perithecia

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Eye3 = Observer’s choice
Eyes3 = Current consensus

Comments

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At least I come to the same conclusion as you…
By: Jason Hollinger (jason)
2012-06-20 04:04:25 CDT (-0400)

Unfortunately I have access to no more info than you, so I end up dead-ended at C. halodytes, too. I agree that this looks like an unstratified cyanobacterial crust, and that together with septate spores apparently leads ineluctably to Collemopsidium. Nice observation, as always. But where to go from here?

Created: 2012-06-19 16:27:32 CDT (-0400)
Last modified: 2012-06-19 16:54:59 CDT (-0400)
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