Rhynchostegium is a genus of pleurocarpous mosses belonging to the family Brachytheciaceae. The genus has a cosmopolitan distribution across different climatological regions except the polar regions, mostly in tropic to north temperate regions. The genus contains both aquatic and terrestrial species. The genus was named for their rostrate opercula. The type species of this genus is Rhynchostegium confertum (Dicks.) Schimp.
Etymology
The genus name comes from the Greek rhyncho- (beaked) and stegos (a lid), which refers to the rostrate operculum of the sporophyte.
History
The genus was first described by Bruch and Wilhelm Philippe Schimper in 1852.
Habitats
Terrestrial species of Rhynchostegium live in moist to wet or shaded habitats, on rock, soil, tree base, tree stem, and logs.
Aquatic species live by or in running water, including streams, springs, rivers, beds of waterfalls, and seepy cliffs.
Morphology
Lamina of Rhynchostegium murale.
A Close view of Rhynchostegium murale sporangium. Rostrate operculum can be seen.
Rhynchostegium are small to large mosses that form either loose tuft or extensive mats on the substrate, with irregular or regular branching. The younger plants are generally deep green or light green; aging plants could become whitish, brownish, or paler green. Stems are creeping and lack hyaloderm, with acute to acuminate pseudoparaphyllia. Stem leaves are erectopatent or erect. Branch leaves are similar in morphology to stem leaves but smaller and sometimes narrower. Leaves are commonly straightly to homomallously arranged; subimbricate, subcomplanate, or complanate arrangement are sometimes seen, especially in branch leaves. Leaf base, decurrent or not, varies from ovate to ovate-cordate, occasionally lanceolate, and the narrowing from gradual to abrupt, towards a short- or long-acuminate apex, where sometimes a differentiated long acumen or apiculus is present. The leaves have a single costa that generally smoothly ends 35-75% up the leaf, and more...
