From the Greek gigas (giant) and spermus (-seeded), in reference to the very large spores.

Monoicous. Plants with an extensive perennial rhizome with erect shoots that often branch verticillately. Shoots numerous, short, forming low compact silvery turfs on soil. Leaves distant to overlapping, delicate, pale green or white, erecto-patent when dry, patent when moist, weakly or strongly cuspidate, often recurved; ecostate.

Perichaetial leaves broadly ovate, upper ones much larger, white and papery at maturity; apex variable, narrowly acuminate, usually tapering to a long flexuose often recurved hairpoint; margin entire to denticulate above. Calyptra minutely mitrate. Setae rudimentary. Capsules immersed, urceolate; operculum a flattened dome with a minute apiculus. Spores angular.

A genus of two or three species, one of which occurs in Australia.

Gigaspermum Lindb., öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 21: 599 (1865).
Type: G. repens (Hook.) Müll.Hal.

Leptangium tumidum Mitt., Trans. & Proc. Roy. Soc. Victoria 19: 66 (1882); Gigaspermum tumidum (Mitt.) Lindb. ex Paris, Index Bryol. 511 (1896). Type: Tas., W.Archer s.n.; holo: NY n.v., fide I.Herrnstadt et al., op. cit. 536 (1980).

This is conspecific with Pleurophascum grandiglobum Lindb. (Pleurophascaceae).

Scott, G.A.M. & Stone, I.G. (1976). The Mosses of Southern Australia: 250-252. (Academic Press, London).

Herrnstadt, I., Heyn, C.C. & Crosby, M.R. (1980). New data on the moss genus Gigaspermum. Bryologist 83: 537–541.

Catcheside, D.G. (1980). Mosses of South Australia: 217-218. (Government Printer, Adelaide).

Delgadillo, C. & Cardenas, A. (1991). Notes on ephemeral mosses from Mexico, including Bruchia paricutinensis sp. nov. Bryologist 94: 294–297.

Stone, I.G. (2012), Australian Mosses Online 37. Gigaspermaceae. Australian Biological Resources Study, Canberra. Version 9 June 2012. http://www.anbg.gov.au/abrs/Mosses_online/37_Gigaspermaceae.html.