From the Greek poly (many) and trichos (a hair), in reference to the hairy calyptra.

Dioicous. Plants tightly to loosely caespitose, whitish green to brown. Stems erect, simple or branched. Rhizoids restricted to the stem base and the bases of the lowermost scale-like leaves. Leaves tightly appressed when dry, erect-spreading to distinctly recurved when moist; lamina linear-lanceolate, gradually narrowing to a sharp apex, with ovate to subquadrate abaxial cells; margin distinctly upcurved, unistratose; sheathing base ovate, gradually or abruptly narrowing to lamina, the sheath cells subquadrate to rectangular with firm walls; costa slightly excurrent, reddish brown, apically sharply serrate with abaxial teeth; lamellae covering almost the entire lamina.

Calyptra hairy. Setae usually solitary, terminal or pseudolateral by subperichaetial innovation, smooth. Capsules inclined, pale to dark brown; urn box-like with 4 distinct angles; exothecial cells distinctly pitted, subquadrate, with firm walls; stomata restricted to the markedly swollen hypophysis; operculum rostellate. Peristome teeth 64, pale brown; epiphragm thin, attached to peristome teeth apices. Spores echinate.

Native.

While the number of described species of Polytrichum is close to 80, the actual number is certainly much lower. The genus is distributed in of both hemispheres. It is represented in Australia by two non-endemic taxa.

Polytrichum is a pioneer plant of open soil and peat.

Polytrichum Hedw., Sp. Musc. Frond. 88 (1801). Type: Polytrichum commune Hedw.

Polytrichum piliferum Schreb. ex Hedw., Sp. Musc. Frond. 90 (1801)

Detailed study of Australian material did not reveal any specimens belonging to this taxon. Obviously, earlier records of the species for Australia are based on misidentification of stunted specimens of Polytrichum juniperinum.

Polytrichum recurvipilum Müll.Hal., Hedwigia 36: 343 (1897). Type: Braidwood district, N.S.W., Nov. 1884, W.Baeuerlen; n.v.

The type material of this species was not available for study, and it is impossible to identify the species from the original description. However, the name is likely to be superfluous, and if the type material can be located, this will probably fall into synonymy under Polytrichum commune or Polytrichastrum longisetum.

J. Hyvönen (2012), Australian Mosses Online 48. Polytrichaceae. Australian Biological Resources Study, Canberra. Version 20 June 2012. 

First published as: J. Hyvönen (2006), Polytrichaceae: Polytrichum, Fl. Australia 51: 140–143. Australian Biological Resources Study, Canberra & CSIRO Publishing, Melbourne.