Observation 102813: Aspicilia knudsenii Owe-Larss. & A. Nordin

When: 2011-09-28

Collection location: Castro Crest, Malibu Creek State Park, Los Angeles Co., California, USA [Click for map]

34.0821° -118.7521° 608m

Who: Jason Hollinger (jason)

Specimen available

HABITAT oldgrowth chaparral and conglomerate outcrops at top of high transverse ridge; SUBSTRATE north face of conglomerate cliff; ASPECT shaded; NOTES thallus tiny gray rimose crust, cortex K-, medulla K+y-o/r, black sunken apothecia with slightly raised white-pruinose margins, epihymenium dark olive-green POL- turning brown in K, hymenium hyaline POL-, cortex POL+ epinecral layer over brown POL- layer over hyaline POL- layer, algae thick and continuous below cortex, medulla POL+ weakly K+y clearing mostly in K, paraphyses with 0-1 cells slightly swollen, conidia rod 12-15 × 1-2 µm; SPORES 25 × 15 µm.

Given K+ medulla, 25µm spores and 15µm conidia, this can only be either A. pacifica or A. anglica. But the paraphyses should be distinctly moniliform for both species. If you relax the restriction on conidia length, it could be A. knudsenii (submoniliform) or A. santamonicae (moniliform). Sonoran Flora mentions specimens with longer conidia. I wonder how important the submoniliform paraphyses are? If important, then this is clearly A. knudsenii.


Thallus, at 30×.
Apothecial section, in water, at 100×.
Apothecial section, in water, at 100x, cross-polarized.

Proposed Names

29% (1)
Based on microscopic features: if conidia length trumps moniliform paraphyses…

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Add Comment
P tests
By: Jason Hollinger (jason)
2017-02-01 12:12:29 CST (-0600)

This can be tricky, especially if (as is usually the case!) there is a mixture of the stictic/norstictic group acids. But in pure this is what I’ve deduced from many more spot tests than I care to admit:

stictic — P+ pure traffic-cone orange with no yellow stage (pannaric and argopsin I think also share this constant unchanging hue, all others start yellow and change hue at least a little)

norstictic — P+ bright yellow turning slightly oranger but always retaining yellow base

salazinic — P+ bright yellow quickly turning orange to sometimes even somewhat red-orange

But note that there may be a mixture of substictic, constictic, connorstictic, etc. as well, and I don’t know what their pure P tests are. So if you get a P+ yellow turning orange, it still could be stictic major with some other minor mixed in. This is primarily of concern in Xanthoparmelia where the chemistry is highly complex; perhaps not so important in Aspicilia.

I will be TLCing many dozens maybe hundreds of specimens of Aspicilia this spring. I am very interested to see first-hand how reliable chemistry is in this genus. If it is as complex as Xanthoparmelia, then there will be unique TLC fingerprints which will dramatically help IDs. If instead it is as reported in Sonoran Flora, usually with just a single secondary substance if any (plus the occasional unidentifiable traces) then I fear chemistry may be overemphasized in the keys. I’m dreading this outcome, but it will be good to know one way or another. Note that all these things — stictic, substictic. norstictic, etc. — are closely related substances (often referred to simply as “stictic acid aggregate”, presumably because the precise mix is often so variable as to be impossible to report definitively); they frequently occur together in minor or trace amounts at least, throughout lichendom.

Stictic vs Norstictic
By: J-Dar
2017-02-01 11:45:04 CST (-0600)

Jason, what color reactions to P signify Stictic vs Norstictic acid major? I have a specimen strongly K+R cortex, K+O medulla, and I didn’t see typical Norstictic acid crystals at 400×.

Verified / corrected observations
By: Jason Hollinger (jason)
2016-03-12 01:40:28 CST (-0600)

Thallus is P+ deep orange indicating at least some stictic acid. There were no crystals in K.

Paraphyses with 1 rarely up to 3 tiny globose end-cells, definitely not fully moniliform.

Spores are consistently 8 per ascus, ~28-30×15-20µm.

Conidia are 10-14µm, avg. 12-13µm.

Created: 2012-07-25 20:13:19 CDT (-0500)
Last modified: 2017-02-01 11:59:18 CST (-0600)
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