Pale Nerve Fissidens Moss

Fissidens pallidinervis and F. elegans are the only species of the genus in North America with small, obscure, pluripapillose laminal cells. Fissidens pallidinervis, however, is distinguished by a rounded to broadly acute leaf apex, and a limbidium restricted to the lower parts of vaginant laminae of perichaetial and one or two pairs of subtending leaves. Axillary, stalked, multicellular, clavate gemmae have been reported in Japanese collections of F. pallidinervis.

Plants tiny. Leafy stems simple, ca. 5.0 mm long, 1.5 mm wide; axillary hyaline nodules not developed; central strand lacking. Leaves in 6–8 pairs, upper leaves lingulate, 0.7–1.1 mm × 0.20–0.25 mm, rounded to obtuse, rarely acute at apex; base of dorsal laminae wedge-shaped; margins serrulate; vaginant laminae 1/2 –2/3 the leaf length, more or less equal; costa ending below the leaf apex; cells of apical and dorsal laminae quadrate to hexagonal, 3.5–8.0(–10) µm long, minutely pluripapillose, thin-walled; cells of vaginant laminae similar to those of apical and dorsal laminae; limbidia marginal, one cell thick, usually appearing only on lower one-half of vaginant laminae of upper leaves or perichaetial leaves. Sporophytes not seen.

Plants to 6 × 1 mm. Stem branched and unbranched; axil-lary hyaline nodules absent; central strand weak or absent. Leaves as many as 18 pairs, lingulate to lanceolate, rounded to obtuse to broadly acute, to 1 × 0.25 mm; dorsal lamina narrowed or rounded proximally, ending at insertion, not decurrent; vaginant laminae ± ¹/2-²/3 leaf length, ± unequal, minor lamina ending near margin; margin serrulate, limbate, ± entire in proximal ¹/3-¹/2 of perichaetial and subtending 1-2 pairs of leaves, limbidium sometimes indistinct, limbidial cells 1-stratose; costa ending 3-25 cells before apex, often spurred distally, bryoides-type; laminal cells 1-stratose, pluripapillose, obscure, firm-walled, irregularly quadrate to hexagonal, 4-8 µm, in transverse section usually twice as deep as wide. Sexual condition rhizautoicous, cladautoicous, rarely gonioautoicous. Sporophytes 1-2 per peri-chaetium. Seta to 2 mm. Capsule theca exserted, erect, radially symmetric, to 0.6 mm; peristome scariosus-type; operculum 0.3 mm. Calyptra cucullate, ± prorate, 0.3 µm. Spores 9-14µm.

Distribution: China, India, Indochina, Malaysia, Africa, and throughout the Americas.

Habitat: on soil or rocks.

Fissidens chungii Thér., Ann. Crypt. Exot. 5: 167. 1932. Type. China: Fujian (Fukien), Ku-shan, Fu-zhou City (Foochow), H.-H. Chung 320 (lectotype PC). Fissidens garberi Lesq. & James, Proc. Amer. Acad. Arts Sci. 14: 137. 1879.

Fissidens garberi Lesquereux & James; F. minutus Thwaites & Mitten