Geothallus tuberosus Campb.

Geothallus tuberosus Campb. Bot. Gaz. 21: 13. 1896
Plant simple or once dichotomous, 5-7 mm. long, 3-5 mm. wide, perennial through the conversion of a large porti on of its axis into an oval or flattened tuber; leaf-like lobes nearly horizontalor somewhat ascending, extremely variable in form, mostly oblong, obovate, or linear-ligulate, 1.5-2 mm. in length, rarely broader than long, sometimes cristate-laminate at base, the margins entire or slightly sinuate; marginal cells pentagonal, or subquadrateoblong, 50-65 X 35 ju, the submarginal hexagonal-oblong or irregularly pentagonal, 50-100 X 35-60 II, those towards the base of the lobes often becoming over 200 ju in length ;antheridial involucre 0.45 mm. in height; capsule 0.8 mm. in diameter, the seta about 90 m long; spores nearly black, 120-150 ju in maximum diameter, spore-wall smooth or very minutely punctulate and very thick (8-12 jx) except as to the comparatively small inner face where it is thinner and bears reticulate ridges, the meshes about 15 ju in width; sterile cells 48-108 ju long.
Type locality: Near San Diego, California.
Distribution: California.