Common Pocket-moss

Fissidens taxifolius is a small to medium-sized moss. It typically grows in dense, yellowish-green to dark green tufts. The plant's upright stems grow 5–22 mm tall and up to 4 mm wide, often branching from the base. Like other members of the genus Fissidens, it has a distinctive flattened appearance, with leaves arranged in two opposite rows that resemble a tiny fern frond. The individual leaves are oblong-lanceolate (spear-shaped) and measure 1.4–2.4 mm in length. A notable characteristic is the leaf tip, which comes to a sharp point (acute) and usually extends into a small projection (mucro or cusp). The leaves have a unique folded structure typical of Fissidens species, with the lower portion forming a sheath that wraps around the stem for half to two-thirds of the leaf length. The species produces smooth rhizoids, unlike some related species like F. osmundoides which has papillose rhizoids (covered with small bumps). Each leaf has a strong central nerve (costa) that typically extends beyond the leaf tip. The leaf margins are finely toothed (serrulate). The cells making up the leaf surface are small, square to hexagonal in shape, and slightly bulging, giving the leaves a cloudy or opaque appearance. These cells measure about 8–10 micrometres (μm) in length, with some variation. The species can reproduce both sexually and asexually. …

Fissidens taxifolius has an incompletely cosmopolitan distribution, being particularly common in the Northern Hemisphere. The species has been documented across Europe, North and South America, Asia, Africa, and the Pacific region. It is absent from Antarctica, very rare in sub-Saharan Africa, and not known from Australia. The species is rare or absent in boreal and arctic regions. It has an exceptionally wide presence, occurring in Algeria, Armenia, Austria, Bermuda, Brazil, Burma, Canada, Chad, Cuba, Denmark, Dominican Republic, Egypt, France, Germany, Guatemala, Haiti Islands, Honduras, Ireland, Japan, Mexico, Netherlands, New Zealand, Norway, Papua New Guinea, Poland, Portugal, Russia, Spain, Sweden, Switzerland, Taiwan, Thailand, Turkey, United Kingdom, and United States of America. Fissidens taxifolius is known to be able to use artificial light to grow in places which are otherwise devoid of natural light, such as Crystal Cave in Wisconsin.

Habitat and ecology. The species typically grows on bare earth in lightly shaded conditions, forming extensive turfs that can cover several square metres when conditions are favourable. It is particularly characteristic of woodland and forest on base-rich and neutral soils, and commonly occurs in stream valleys and rocky slopes. …

The species exhibits different reproductive patterns across its range. In Europe and North America, it is autoicous, meaning both male and female reproductive organs are found on the same plant. However, in other regions including New Zealand, Hawaii, and Papua New Guinea, populations appear to be dioicous, with male and female reproductive organs on separate plants. In some Pacific regions, only female plants have been found, and the species appears to reproduce primarily through vegetative means rather than spore production.