Archegonial plants 1--1.5 mm long, bifurcate, sometimes with an elongated branch, becoming reddish or purplish at the margins, lobes wedge-shaped, ca. 550 µm wide with quadrate marginal cells; involucres cylindric to obovate, 0.5--1.1 mm high, crowded over the thallus and nearly obsuring it. Antheridal plants ca. 1--1.5 mm long, lobes somewhat wedge-shaped; marginal cells isodiametric, involucres flask-shaped, to 365 µm high. Sporangium 335--595 µm. Spores remaining in tetrads at maturity, 65--155 µm, brown to dark-brown; lamellae granulate and occasionally lobed, running parallel to one another or nearly so, occasionally branching, lacking tubercles; not reticulate.

Soil; low elevations; known only from Calif. (San Diego county).

This and the following species are the rarest of the North American Sphaerocarpos.