Plagiomnium venustum

It has green to green-yellow leaves that start large near the apex and become smaller and more distant from each other as they descend.[2] They can range from obovate to elliptic in shape and between 3-7mm in length.[2] This means that they are widest near the middle and get more narrow as they reach the leaf tip. The leaves contort and twist when dry, which can be due to the lack of stereids in the costa of the leaves, and spread out when exposed to water.[1] Because stereids are not present to give structural support to the leaves, they easily twist. This is a unique characteristic of Plagiomnium venustum from all the other Plagiomnium species. The leaves have a toothed margin with elongated cells near the margin borders that get smaller as they approach the center.[1] The lamina and marginal cells are unistratose and multiseriate of approximately 3-5 series.[7]

Sporophytes with nodding sporangia and dry twisted leaves

The sporophyte are attached to the gametophyte by a foot. They have a 3-4cm long seta that is red at the base.[2] Plagiomnium venustum have nodding sporangia with a distinct brown neck.[2][8] The capsule is oblong and attached to a wrinkled, brown, apiculate operculum underneath.[2] Like most mosses of the Bryopsida class, Plagiomnium venustum contain papillose exostome teeth and endostome peristome teeth.[9] The sporangial jacket contains mammillose stomata guard cells that are easily visible because of their dark colour.[2] Maturation of the sporophyte happens from mid-spring to early summer, in which the spores are released.[2]

Plagiomnium venustum is a species of moss that belongs to the genus Plagiomnium. Plagiomnium mosses are known for forming mats on their substrates. The leaves of these mosses are green and generally erect and are shaped obovate or elliptic with unistratose leaf margins. They contort when dry and spread out when damp. They have brown rhizoids. Plagiomnium also have sterile stems (except for P. venustum). On the ventral side of the leaves are a costa and many lamellae. The sporangia are nodding due to a bent seta with a capsule, operculum, and arthrodontous exostome and endostome teeth. The sporangia are covered with a hairy calyptra.[10]

There are currently 102 species names that belong to the genus Plagiomnium (many of which are synonyms), but only 34 have been accepted. Listed below are the 34 accepted Plagiomnium species:[11]