Mannia pilosa (Aytoniaceae, Marchantiophyta) — new to the Japanese Flora

Abstract

Mannia pilosa (Hornem.) Frye & L.Clark, a circumpolar species widely distributed in arctic-alpine regions was newly found from Mt. Kitadake, with its 3192 m peak the second highest mountain in Japan. Plants of M. pilosa were growing in an alpine meadow on a limestone outcrop about 400 m south of the peak at 35°40’ N, 138º 14’ E, ca. 3000 m alt. The isolated Japanese population for M. pilosa seems to be a glacial relict. New information on spore morphology using SEM and habitat of the Japanese plants is provided.