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PHYLLOGONIACEAE

(B.J. O'Shea)

A monotypic family.

Phyllogonium Brid.

Three species in Africa: P. fulgens (Hedw.) Brid. (Réunion, and also South Atlantic islands (Tristan da Cunha, Gough), Mexico, West Indies, Surinam, tropical Andes), P. viride Brid. (Réunion, and also South Atlantic islands (Tristan da Cunha), Mexico, West Indies, Surinam, Bolivia, SE Brazil), P. viscosum (P. Beauv.) Mitt. (South Africa, Madagascar, possibly Mauritius, Réunion and also South Atlantic islands (Tristan da Cunha), Mexico, tropical Andes); the genus exhibits a tropical American-African distribution.

Plants medium sized to rather large, forming long pendent strands from loose mats, glossy green, yellowish-green or golden-brown. Primary stems creeping; leaves scale-like. Secondary stems usually pendulous, to 50 cm or more, irregularly pinnately branched, few to many; in cross-section outer 2-4 rows of cells small, thick-walled, inner cells larger, rather thick-walled, central strand absent; pseudoparaphyllia foliose. Leaves loosely imbricate, usually appearing 2-ranked, ovate-oblong to oblong, 2.5-4.5 mm long, deeply concave and compressed laterally, smooth or undulate, apex rounded or truncate, apiculate and recurved or erect, base auriculate; margins plane, entire; costae absent or short and forked; laminal cells smooth and strongly porose throughout, median cells linear to oblong-rectangular; alar cells differentiated, shortly rectangular to subquadrate-rounded, strongly porose, usually rusty-red. Dioicous. Perichaetia lateral, leaves differentiated, abruptly long acuminate from an broadly ovate base. Seta short to somewhat elongate, 0.5-3.5 mm long, equal to or longer than capsule, smooth. Capsule shortly exserted or immersed, suberect, urn oblong-cylindrical to ovoid, 1.2-2.5 mm; exothecial cells mostly quadrate, ± thick-walled; stomata present or absent; annulus absent. Operculum conic-rostrate, oblique. Prostome present, represented by 1-3 layers adnate to the exostome. Peristome single or double, exostome teeth 16, smooth; endostome absent or if present represented only by a low, hyaline basal membrane. Calyptra mitrate or cucullate, sparsely to densely hairy. Spores spherical, papillose.

Habitat. Commonly epiphytic on branches and occasionally trunks of trees, treelets and shrubs, less often on humus or leaf litter, particularly on steep banks; lowland adjoining montane or premontane to more commonly in mid and high montane forests, 150-4200 m.

Discussion. Phyllogonium is characterised by the pendent habit, 2-ranked, oblong or oblong-ovate, conduplicate leaves, apiculate or truncate apex, auriculate base, short and forked costae, and strongly porose laminal cells. The genus is typically found in montane forests, and is one of the more conspicuous pendent mosses. The species can be distinguished by the following features:

The African distribution of this genus needs further study: for instance Lin (1983) mentions no collections from Madagascar despite there being at a number of published collections, and also there seems some discrepancies amongst early authors about which islands were visited by which collectors.

Literature. Lin, S.-H. 1983. A taxonomic revision of Phyllogoniaceae (Bryopsida). Part I. Journal of the Taiwan Museum 36(1): 37-86 [keys, illustrations, maps].

accepted 4.05.2005