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EUSTICHIACEAE

(B.J. O'Shea)

A monotypic family.

Eustichia (Brid.) Brid.

There is only one species worldwide in this genus, E. longirostris (Brid.) Brid., which is distributed at high altitudes in central and south America, and in southern Africa (South Africa and Lesotho) and in the southern ocean islands of Marion and Tristan da Cunha. Records for Madagscar and Réunion were errors based on the Tristan collections.

Plants slender and small, forming loose to rather dense tufts, light to olive green. Stems erect, to 5 cm tall, freely branched, radiculose below, with only the top 1-2 cm above ground; in cross-section central strand present. Leaves 2-ranked above, spirally arranged scale-like leaves at stem base, erect to erect-spreading, little altered when dry, conduplicate to carinate-concave, short oblong-ovate, 0.5-0.8 mm long, apex inwardly hooked, short acuminate; margins plane, erose-denticulate throughout except at base; costa single, short excurrent; laminal cells thick-walled, median cells subquadrate to short oblong-quadrate, 3-4 low, blunt papillae on dorsal surface, ventral surface smooth; basal cells short rectangular, smooth; marginal cells appearing mostly smooth; spirally arranged leaves on lower stems and branches ovate-short lanceolate, acuminate, costa rather long excurrent. Dioicous. [Perichaetia appearing lateral, leaves convolute, oblong, apex abruptly narrow acuminate; costa rather long excurrent; laminal cells elongate. Seta elongate, to 15 mm long, smooth. Capsule mostly erect, urn short obloid, 0.8-1.2 mm long, when deoperculate usually ribbed with mouth flared; exothecial cells irregularly elongate; thick-walled, stomata several at base of urn, superficial. Operculum conic-long rostrate. Peristome single, teeth 16, joined at base, usually reduced, vertically striate-papillose. Calyptra cucullate, naked and smooth. Spores lightly papillose.]

Habitat. On soil among rocks in the sub-alpine grasslands and shaded banks and dripping rock faces in ravine woodland of the Drakensberg mountains of Lesotho and South Africa (Natal and Orange Free State), 900-3100 m.

Discussion. Eustichia is characterized by the strongly 2-ranked leaves with pluripapillose laminal cells and a short excurrent costa that is slightly incurved. The stem is often quite long, with more than half of the stem buried. The sporophyte is not known in Africa. Further investigations are needed to elucidate its phylogenetic position of the family. Magill (1987) has a good description and illustration of South African material, with distribution map.

References. Allen, B. 2002. Moss Flora of Central America Part 2. Encalyptaceae-Orthotrichaceae. Monographs in Systematic Botany of the Missouri Botanical Garden 90: 1-699 [p. 451-453: description, illustration]. Magill, R.E. 1987. Bryophyta. Part I. Mosses. Fasc II. Gigaspermaceae - Bartramiaceae. In: O.A. Leistner (ed.) Flora of Southern Africa. Pretoria: Botanical Research Institute [p. 399: description, illustration, map].

accepted 20.04.2000