From the Greek holos (complete) and mitrion, the diminutive of mitra (a headband, headdress or turban), possibly alluding to the large calyptra that covers the entire capsule.

Pseudoautoicous. Female plants small to medium-sized, growing in turfs. Stems erect to ascending, tomentose, densely foliose; central strand present; flagelliferous branches occasionally present. Leaves falcate-secund to erecto-patent when moist, not much altered or crispate or spirally contorted when dry, subulate; alar patches single-layered; margin serrate to crenulate, rarely almost entire; border differentiated or not; costa strong, subpercurrent to percurrent, abaxially smooth or with a few apical teeth. Basal laminal cells elongate to linear, thick-walled, pitted; upper laminal cells isodiametric, not pitted.

Perichaetial leaves sheathing or clasping at the base, sometimes overtopping the capsule. Calyptra cucullate. Sporogones solitary or aggregated; capsule exserted, ovoid to cylindrical, straight; stomata present at base of capsule, phaneropore; annulus present. Peristome teeth undivided, fenestrate or irregularly split, densely papillose on the outer surface or on both sides. Spores spherical, finely papillose.

Species of Holomitrium are recognised by leaves that are mostly crisped or spirally contorted when dry, conspicuous perichaetia, straight capsules on a comparatively long seta, and entire or fenestrate to irregularly split, papillose peristome teeth.

Holomitrium is a medium-sized, mainly tropical genus of perhaps 40 species, although some species occur at temperate latitudes in the Southern Hemisphere. In Australia and New Zealand a single species, H. perichaetiale, has been recognised, but recently a second taxon, H. trichopodum, was transferred from Dicranoloma (Klazenga, 2006) based on molecular and peristome characters.

Holomitrium Brid., Bryol. Univ. 1: 226 (1826), orth. cons. Type: H. perichaetiale (Hook.) Brid.

Holomitrium dietrichiae Müll.Hal., Linnaea 37: 149 (1872). Type: Brisbane River, Qld, 1864, A.Dietrich; holo: B (destroyed).

The type was destroyed together with the rest of Müller’s herbarium in the conflagration of the Berlin herbarium during the Second World War. No isotypes have been located.

Key to species

Leaves erecto-patent to homomallously curved when moist; distal part curled up when dry .......... H. perichaetiale

Leaves falcate-secund, not greatly altered when dry ........................................................................... H. trichopodum

Ramsay, H.P. (1986). Studies on Holomitrium perichaetiale (Hook.) Brid. (Dicranaceae: Bryopsida). Hikobia 9: 307–314.

Klazenga, N. (2003). A revision of the Australasian species of Dicranoloma (Bryophyta, Dicranaceae). Australian Systematic Botany 16: 427–471.

Klazenga, N. (2006). Holomitrium trichopodum (Bryophyta, Dicranaceae), a Holomitrium with split peristome teeth from Australia and New Zealand. Journal of the Hattori Botanical Laboratory 100:
293–303.

Klazenga, N. (2012). Australian Mosses Online 33. Dicranaceae. (Australian Biological Resources Study: Canberra). Version 30 May 2012; https://www.anbg.gov.au/abrs/Mosses_online/33_Dicranaceae.html [Accessed July 2019]

Klazenga, N. (2012). Australian Mosses Online 33. Dicranaceae. (Australian Biological Resources Study: Canberra). Version 30 May 2012; https://www.anbg.gov.au/abrs/Mosses_online/33_Dicranaceae.html [Accessed July 2019]