Guide to Liverworts of Oregon: Key to Genera 67
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<1a plants thallose > 2b chloroplasts numerous > 62a thallus tissue homogeneous > 63b thallus ribbon like > 65b ventral scales absent > 66b thallus without hairs > 67
(Riccardia latifrons, Cape Perpetua, Linclon Co., Oregon. DHW XXXX)
67a Sex organs on short ventral or lateral branches; submarginal cells of thallus mostly much less than 50 μm; thallus pinnately or palmately branched, less
than 3 mm wide (except Aneura); rhizoids sparse
(Couplet 68)
Left: Pellia neesiana, Lincoln County, Oregon.
67b Sex organs on dorsal surface of thallus; submarginal cells of thallus often longer than 100 μm; thallus more or less dichotomously branching, usually
more than 5 mm wide; rhizoids numerous
(Couplet 69)