TYPE: U.S.A. California. Los Angeles Co, Santa Monica Mountains, Topanga Canyon. On sandstone, 1908, H.E. Hasse 1102 (FH!, lectotype). 

Description. Thallus endolithic with algal clusters in substrate, sometimes forming thick layer below apothecia or in mycelial base, algal cells 8–12 μm wide.  
Apothecia dispersed, becoming contiguous through replication by division, usually round, (0.2–)1.0–2.0 mm wide, 300–500 μm thick (up to 1 mm thick including mycelial base or stipe), disc black, reddish black when wet, epruinose, even with or slightly lower than margin in early development, slowly becoming convex, eventually excluding the margin, becoming immarginate. Margin 60–110 μm thick, of radiating hyphae, outer layer melanized, hyphae usually visible, shading into inner reddish layer. As the apothecia become more convex, and wider than the base, the margin is excluded, and the melanized layer is observed below the edge of the apothecium extending under the apothecium.
Apothecia at first broadly attached to the substrate, usually becoming wider with a mycelial base up to 500 μm thick, or stipitate (stipe half or less than width of apothecia), especially in process of replicating by division sometimes forming pulvinate clusters on a single undivided mycelial base as in the lectotype. Hymenium usually 100–125 μm tall, hyaline, but orange in thick section, epihymenium yellowish to dark reddish black, coherent, 15–25 μm thick, paraphyses 1.5–2.0 μm wide, apices usually not expanded in wider gel cap, hymenial gel IKI+ red or blue to red, hemiamyloid. Asci 50–85 × 12–14 μm wide, sometimes cylindrical, and thinner, height variable, ascospores ellipsoid 3–5 ×  1.5.–2.0 μm  wide. Subhymenium 20–34 μm high, IKI+ blue, euamyloid. Narrow distinct hypothecium below the subhymenium. Medulla usually obscure, of intricate hyphae 3–4 μm thick, developing into an elevated mycelial base, sometimes reduced to a stipe after division, up to 500 μm thick.
Pycnidia not observed and expected to be rare.

Chemistry. Not producing secondary metabolites.  

Distribution and ecology. In the Sonoran Desert region in Arizona where S. similis is rare, extending to southern California where it becomes sympatric with S. similis, on silicate rock, sandstone, and quartzite in full sun.

Differentiation. Sarcogyne californica differs from S. similis in becoming convex and eventually becoming immarginate and in not producing psoromic acid. When apothecial disc has not become distinctly convex it looks like S. similis. Sarcogyne californica differs from S. novomexicana or S. mitziae in having a black margin instead of a brown margin. It differs from S. hypophaea in having a continuous unsegmented margin instead of a segmented angular margin. It differs from S. plicata, which  usually has narrow elongate apothecia with discs that do not turn red when wetted.  

Discussion. Sarcogyne californica was originally treated as a synonym of S. similis in the Sonoran Flora (Knudsen & Standley, 2007), but it is now no longer considered a synonym, distinguished by its convex apothecia becoming immarginate, a lack of psoromic acid, and its phylogenetically distint position within the family (Knudsen, in press). 

LITERATURE:

Knudsen, K. & Kocourková, J. (2020) Lichenological Notes 7: On taxa of Acarospora and Sarcogyne. Opuscula Philolichenum 19: 158-162.

Knudsen, K. & S. M. Standley (2007) Sarcogyne. In: T. H. Nash III, C. Gries & F. Bungartz (eds.) Lichen Flora of the Greater Sonoran Desert Region. Volume III. Lichens Unlimited, Tempe, p. 289–296. 

Lendemer, J.C., Bungartz, F., Morse, C. & Manzitto-Tripp, E.A. (2022) Sarcogyne similis (Acarosporaceae) produces psoromic acid and is confirmed to be widespread in North America. The Bryologist 125(1): 91-101.