Päärynäsuppusammal

Physcomitrium pyriforme is morphologically variable and widespread across the continent. Plant size, leaf characters, and shape of the capsule vary from place to place and often within populations.

Plants light green or yellowish green. Stems 0.2-15(-25) cm. Leaves obovate to ovate-lanceolate, distal leaves 2-5 mm; margins toothed, sometimes nearly smooth distally; percurrent to rarely short-excurrent. Specialized asexual reproduction absent. Seta (1-)6-15(-30) mm. Capsule exserted, 1-3 mm, globose-pyriform when young, highly variable in shape when old, urceolate to pyriform; neck short, distinct; exothecial cells irregular hexagonal; suboral cells consisting of 5-17 rows of rectangular cells. Spores (24-)46-60(-90) µm, papillose.

Gymnostomum pyriforme Hedwig, Sp. Musc. Frond., 38. 1801; Physcomitrium californicum E. Britton; P. drummondii E. Britton; P. kellermanii E. Britton; P. megalocarpum Kindberg; P. pygmaeum James; P. turbinatum (Michaux) E. Britton

Physcomitrium pyriforme, commonly known as common bladder-moss, is a bryophyte native to all continents except South America and Antarctica. Its capsules mature beginning in late fall and through the spring. It is most commonly found in wet soils in disturbed locations. A highly variable species, size, leaf characters and shape of the capsule vary across its range, but often within populations as well.