Zygodon californicus Hampe ex Müller Hal., Bot. Zeitung (Berlin) 20: 361. 1862

Plants 1-4 cm. Stem leaves linear-lanceolate, 1.5-4 mm; margins recurved, toothed or entire proximally, toothed or notched distally; basal laminal cells yellowish, walls thick; distal cells 9-11 µm, slightly obscured by papillae, papillae elliptic, small. Sexual condition dioicous; perichaetial leaves elongate, narrow, base subsheathing, apex long-pointed. Seta 1.5-2 mm. Capsule immersed to emergent, 1.2-1.6 mm; operculum conic-apiculate, less than diam. of capsule. Spores 10-15 µm.

Crevices of neutral to acidic rock; moderate elevations; B.C.; Calif., Idaho, Oreg., Wash.

Amphidium californicum is distinguished by the linear leaves with notched distal margins. Amphidium lapponicum has decidedly broader leaves and distal cells obscured by large, warty, cuticular papillae.