When: 2016-10-21

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

35.8271°N 120.3243°W 408m [Click for map]

Who: J-Dar

Specimen available

On intruded rock outcrop in semi-arid grassland habitat, north and east aspects.

Thallus areolate, white pruinose. Ascomata not found. Perethecia in photos I think are from a lichenicolous fungi. Couldn’t get any conidia. Thallus K-, C-, KC-. The perethecia shown in photos have 8 spores/ascus, spores are simple, ellipsoid, hyaline, 16-17×5-6µm.

Not sure what I have here.


Perethecia 1-3/areole.
Pycnidia I think

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Add Comment
Good work
By: Jason Hollinger (jason)
2016-10-23 23:33:39 CDT (-0400)

Didn’t mean to suggest this was parasitic, just that it looked like a species which happens to be parasitic. And I wanted to mention that it can be hard to tell if a well-developed specimen started parasitic in the dim past. But if the microscopic details are all off, then forget my suggestion!

Your theory that the perithecia belong to a lichenicolous species is also good. Definitely worth keeping in mind. The conidia might even belong to the host, by the way. Tricky!

I suppose a way to confirm Verrucaria is to check if the paraphyses/paraphysoids dissolve by maturity. Even then, some lichenicolous genera might belong to Verrucariales.

Yes, Verrucaria looks good
By: J-Dar
2016-10-23 22:56:31 CDT (-0400)

I can’t confirm from the pieces I brought home that this specimen is parasitic on Staurothele, but it looks like photos of Verrucaria bernardinensis. I re-did the micro to see where it could fall, unfortunately the spore size and conidia size don’t fit with any of the parasitic species:

Spores ellipsoid, ave 19.6×6.9µm (N=6) (see photos)
Conidia: Baciliform, rough average is 3.8×1.5µm (see photos)

Verrucaria bernardinensis has (sub)globose spores, which these clearly are not. Based on spore size it keys closest to Verrucaria cetera, but this species has conidia 7.5-12µm, not even close to what I have. Verrucaria inficiens is also close, but not good enough of a match. If we consider the possibility that this is not parasitic, then it could go toward something like Verrucaria subdivisa.

I guess another Verrucaria sp. for the box.

By: Jason Hollinger (jason)
2016-10-23 12:34:38 CDT (-0400)

(or V. bernaicensis, I always get them mixed up). It’s a parasitic species found on Staurothele spp. Very common in Great Basin. Worth considering. Well-developed populations can be hard to even find the original Staurothele host.