When: 2018-05-25

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

34.4767°N 119.9988°W 216m [Click for map]

Who: J-Dar

Specimen available
Collection number: Jason Dart 1002

On smooth bark of younger coast live oak (Quercus agrifolia) trunk, about a mile from the ocean above El Capitan State Park.

Thallus an indeterminate areolate crust, greenish, matte, thin, without soredia or blastidia. Apothecia common, beginning plane with thick thalline margin concolorous with thallus, becoming convex with a reduced margin. Disk black, epruinose. Epihymenium dark brown, POL-. Hymenium hyaline, IKI+blue persistent, paraphyses simple, not very conglutinated. Hypothecium hyaline.

Spores 1-septate, becoming brown, bean shaped, with apical and septal swellings (Physcia type) with a light torus. Septa becoming slightly swollen in KOH. Spores mounted in Lugol’s and heat treated (see photos): Average size 14.3×7.7 (n=20).

I first put this at either Rinodina laevigata or Rinodina santae-monicae. Septal swelling doesn’t seem sufficient to push these into Dirinia-type spores for santae-monicae. But the spores seemed too small so I measured 20 and the average is way too small for either of these species. I’m looking at Rinodina freyi now but haven’t made a final determination.


100x in water
IKI (Lugol’s) + Blue hymenium
400x IKI
400x IKI

Proposed Names

28% (1)
Recognized by sight
57% (1)
Used references: Sheard 2010 Monograph. Sonoran Flora V2
Based on microscopic features: Spore type and size
Based on chemical features: Epihymenium P-

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= Observer’s choice
= Current consensus


Add Comment
Updated micro
By: J-Dar
2018-06-15 19:34:36 PDT (-0700)

Looking closely at cross-polarized view of thallus cortex shows crystals that I’m assuming are atranorin (see photo). The epihymenium was POL- and also P- under the cover slip at 100×. Spores originally measured small, but another review with fully mature (=brown) spores showed a higher average size of 16.2×9.1µm (n=13), with a l/w ratio of 1.8. Rinodina californiensis seems the best fit, but I’m still a bit hesitant.

Created: 2018-06-05 18:54:13 PDT (-0700)
Last modified: 2018-06-15 19:34:37 PDT (-0700)
Viewed: 37 times, last viewed: 2019-04-23 14:12:52 PDT (-0700)
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