Plants small or large, pale green to red-green. Stems gemmiform to evenly foliate, sometimes in 2 or more clumps along stem, innovations and fertile stem-leaves somewhat differentiated, innovations not julaceous; rhizoids redbrown to red. Leaves imbricate, sometimes slightly twisted when dry, ovatelanceolate, concave; base not decurrent; margins entire to serrulate distally, limbidium present or sometimes absent; costa not reaching apex to long-excurrent; inflated group of pinkish subalar cells present on larger distal leaves of fertile stems; medial and distal laminal cells rectangular to hexagonal. Specialized asexual reproduction by deciduous brood branchlets in leaf-axils, rarely by rhizoidal tubers. Sexual condition dioicous. Capsule nutant, pyriform, 2–3 (–4) mm; hypophysis slender, gradually tapered to seta, not inflated and rugose; peristome well developed; endostome not adherent to exostome, basal membrane high, segments well developed, cilia long, appendiculate.

Distribution

Nearly worldwide except Antarctica, boreal-temperate, Mediterranean climates

Discussion

Species ca. 6 (3 in the flora).

Section Caespitibryum includes Gemmabryum caespiticium and several narrowly defined segregates. The group is tentatively placed in Gemmabryum. In some respects the species are reminiscent of species in Ptychostomum sect. Cladodium, especially P. creberrimum. Plants of sect. Caespitibryum have acuminate leaf apices and red-brown capsules.

Selected References

None.

Lower Taxa

Gemmabryum badium, Gemmabryum caespiticium, Gemmabryum kunzei

Key

1	Plants small; leaves usually smaller than 1 mm; distal lamina hyaline with age; distal laminal cells short-rectangular to hexagonal, (2-)3-4:1; proximal cells abruptly quadrate, 1-2:1; costae variable, at least some long-excurrent, awns green to hyaline; specialized asexual reproduction unknown.	Gemmabryum kunzei
1	Plants large; leaves 0.5-2(-3) mm; distal lamina not or occasionally hyaline with age; distal laminal cells long-hexagonal, (3-)4-6:1; proximal cells abruptly quadrate to rectangular, 2-4:1 along costa; costae usually long-excurrent, awns brown, yellow-brown, or sometimes hyaline; specialized asexual reproduction by rhizoidal tubers or brood branchlets	> 2
2	Leaves strongly concave; costal awns longer than 1/2 leaf length, often as long as leaf, denticulate; rhizoidal tubers absent.	Gemmabryum badium
2	Leaves weakly to moderately concave; costal awns usually shorter than 1/2 leaf length, smooth or rarely somewhat denticulate; rhizoidal tubers sometimes present.	Gemmabryum caespiticium

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