Octoblepharaceae

By L.T. Ellis

(fide Eddy 1990)

Shoots erect. Leaves linear, extending from a subelliptical semisheathing base; costa incrassate, occupying entire leaf above the base; leucobryoid, with a unistratose median network of chlorophyllose cells between several dorsal and ventral layers of hyaline cells, chlorophyllose cells in cross-section mostly trilateral (quadrilateral in proximal leaf); lamina restricted to leaf base, unistratose, hyaline, porose. Gemmae rare, produce at apices of leaves, fusiform, uniseriate. Monoicous. Sporophytes terminal; seta exserted, smooth; theca cylindrical, operculum rostrate. Peristome haplolepidous (8 or 16 teeth with fine reticulations). Calyptra dimidiate, fugacious. Spores papillose.

NB. Mosses in the Octoblepharaceae are distinguishable from those in the Leucobryaceae by their possession of leaves with chlorophyllose cells that are trilateral in cross-section rather than quadrilateral, and by their possession of flattened, broadly rounded leaf apices. African Leucobryaceae possess leaves with acute-subacute apices.

Octoblepharum albidum Hedw., Sp. Musc. Frond. 50, 1801. (Fig. 11)

Shoots <1->3.5 mm high. Leaves 5-11 mm long, spreading to reflexed, structure as described under genus; leaf margin in limb formed by a narrow strand of thin-walled, linear, hyaline cells, near leaf apex sometimes giving rise to small teeth; in leaf base margin not differentiated, entire to sinuose. Gemmae sometimes produced at leaf apices, fusiform, uniseriate. Autoicous; perigonia in leaf axils, bud-like; inner-perigonial bracts elliptical and acutely pointed, formed by sheathing hyaline lamina with a much reduced costa that ends below leaf apex; perichaetia terminal. Seta <5-10 mm long; capsule >1-2 mm long, cylindrical, with a few superficial stomata around base; operculum rostrate. Calyptra dimidiate, largely smooth and straw-coloured, with a reddened apex. Peristome teeth 8, mostly 125-200 µm long, with fine, anastomosing reticulations (teeth frequently broken or degenerate and reticulations not always apparent). Spores (17.5-)20->22.5 µm diameter, papillose.

Octoblepharum albidum has a pantropical distribution and is the sole representative of Octoblepharum occurring in Africa. Other species in the genus are restricted to the New World.

Octoblepharum albidum occurs from sea level to above 1500 m a.s.l.. but is probably more frequent in the forests, parks and gardens in lowland areas. Commonly colonising living and fallen trunks and branches of trees, it has also been found on moist rock, and humus overlying rock.