Rhizoidal gemmae were first found in Archidium ohioense Schimp. ex C. Mull. from Japan. They are filamentous (0.5-1.5 mm long, 100-140μm wide), blackish-brown, sometimes hyaline at apices. The gemma cells are barrel shaped, 100-160μm long, rich in oil drops. Most cells have at their mid-section single small cells (Arts 1991 called them "initial cells"). Rhizoidal gemmae in Archidium ohioense are quite similar in size and shape to those in A. alternifolium (Arts 1990) and A. thalliferum (Stone 1985). These gemmae are similar to those on Campylopus (Arts, 1989) and Ditrichum (Matsui et al., 1985).
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