Homomallium

Plants medium-sized, in dense, flat mats, dark green, brownish, or yellowish, glossy or somewhat shiny. Stems creeping, irregularly branched; hyalodermis absent, central strand absent; pseudoparaphyllia foliose. Stem and branch leaves similar, erect-spreading or homomallous, oblong-ovate, not plicate; base not decurrent; margins erect or occasionally reflexed proximally, entire or serrulate distally; apex abruptly acuminate, subulate or not; costa double and short or ecostate; alar cells differentiated, quadrate or quadrate-rectangular; laminal cells smooth; distal cells ca. 4–6:1. Specialized asexual reproduction by dense axillary clusters of short brood branches. Sexual condition autoicous; perichaetial leaves erect, oblong, apex acuminate. Seta yellow-orange, red, or purple. Capsule inclined to horizontal, oblong-cylindric, asymmetric, arcuate, contracted below mouth; annulus 1- or 2-seriate, deciduous, cells large; operculum convex-conic, apiculate to short-rostrate; peristome double; exostome teeth with external surface cross striolate basally, papillose distally; endostome basal membrane distinct, segments keeled, cilia 1 or 2, nodulose. Calyptra naked. Spores round, smooth to minutely papillose.

Distribution

North America, Mexico, Asia, Australia.

Discussion

Species 13 (3 in the flora).

Homomallium is a medium-sized moss that lacks the characteristic secund leaves and longer cells found in other hypnaceous mosses. The genus is distinguished from closely related genera by its short leaves with smooth, shortly rhomboidal distal laminal cells, numerous quadrate alar cells, and inclined-horizontal capsules with a well-developed peristome. The plants are closely appressed to the substrate; the stem has small, thick-walled epidermal cells and sparse, 1–3-celled axillary hairs; the seta is flexuose; the capsule stomata are limited to the urn base; the exostome teeth are yellow or orange; the endostome segments are hyaline and papillose; and the spores are yellow to yellow-brown. Homomallium sharpii Ando & Higuchi of Mexico may eventually be found in the flora area (see under 1. H. adnatum).

Selected References

None.

Lower Taxa

Homomallium adnatum, Homomallium incurvatum, Homomallium mexicanum

Key

1	Leaves erect or slightly homomallous, not falcate-secund.	Homomallium adnatum
1	Leaves erect to spreading, homomallous to slightly secund	> 2
2	Leaf apices subulate; distal laminal cell walls thin; setae reddish.	Homomallium incurvatum
2	Leaf apices not subulate; distal laminal cell walls thick; setae yellow-orange.	Homomallium mexicanum