GBA onlineBRUCHIACEAE(J.-P. Frahm)
Discussion. The Bruchiaceae were originally included as a subfamily (Trematodontoideae) in the Dicranaceae but re-established as a family by Buck (1979). It includes four genera: Bruchia, Pringleella (3 species), Eobruchia (2 species) and Trematodon, of which only Bruchia and Trematodon are represented in Africa. Magill (1981) includes also Cladophascum in this group, which is treated here in the Dicranaceae. The family contains more than 100 species worldwide. Literature. Buck, W. R. 1979. A re-evaluation of the Bruchiaceae with the description of a new genus. Brittonia 31: 469-473. Magill, R.E. 1981. - see General refs.
A genus of about 17 species, which are mainly distributed in the northern hemisphere, especially in North America. Only 3 species are known from Africa, Bruchia brevipes Harv. ex Hook. and B. eckloniana Müll.Hal. from South Africa and B. queenslandica I.G.Stone (B. foveolata Magill) from Namibia, which are keyed out and illustrated by Magill (1981 - see General refs.). Plants very small, scattered or in small groups. Stems short, to 5 mm tall, simple. Leaves erect to erect spreading, larger above, from an ovate or oblong base lanceolate or linear-lanceolate, subulate, 1-2 mm long, acute to acuminate; margins plane, entire or serrulate; costa subpercurrent to short excurrent, rather weak; upper laminal cells narrowly rectangular, thick-walled; basal cells broader, oblong-rectangular, rather lax. Perichaetial leaves larger than stem leaves. Seta short, 0.3-0.4 mm long. Capsule immersed, urn pyriform, 1 mm long, neck distinct, 1/4-1/3 of the length of the urn, with numerous phaneropore stomata, lid with short beak. Operculum and peristome absent. Calyptra mitrate, smooth, base lobed. Spores large, 25-45 µm, papillose to spinose. Habitat. On open soil, together with other ephemeral mosses. Discussion. Plants of this genus are characterised by their small size, cleistocarpous capsule (lacking an operculum and peristome) immersed in the leaves. They are distinguished from other cleistocarpous short-lived mosses by the differentiated neck with numerous stomata. Literature. Rushing, A. E. 1985. Spore morphology in the genus Bruchia Schwaegr. (Musci). American Journal of Botany 72: 75-85. Rushing, A. E. 1986. A revision of the genus Bruchia Schwaegr. (Musci). Journal of the Hattori Botanical Laboratory 60: 35-83 [keys, illustrations]. A genus much in need of a revision in which 81 species have been described, of which one third were described once and never reported again. Twenty-six species are known from Africa, of which only a few species are widespread. Plants gregarious or forming low, loose tufts, green to yellowish-green. Stems mostly short and erect, 1-2 mm long, in some species up to 8 mm long, radiculose. Leaves flexuose or contorted when dry, erect to erect-spreading when wet, lanceolate to broadly subulate from an ovate or oblong sheathing base, 1.5-4.0 mm long, apex acute to subobtuse; margins plane, entire or with a few teeth at apices; costa subpercurrent; upper laminal cells subquadrate or rectangular above leaf shoulders, uni- or bistratose; lower and basal cells rectangular to oblong hexagonal, lax. Perichaetial leaves convolute, longer than stem leaves. Seta elongate, 2-20 mm long, slender, yellowish. Capsule erect to inclined, urn cylindrical, 1.2-3.0 mm long, sometimes strumose, with a distinct neck equal to or much longer than urn. Operculum long rostrate, oblique, 0.5 – 1.5 mm long. Peristome present and single, rudimentary (consisting of a basal membrane) or absent; teeth vertical-striate, perforate. Calyptra cucullate, naked. Spores 20 – 30 µm, papillose. Habitat. On open soil, often in disturbed sites in villages or along roadside banks; from the lowland to 2500 m. Discussion.
The genus is characterised by capsules with a conspicuously long
neck, which is otherwise only found (rarely) in Bryaceae. Click here for pdf file uploaded 17.04.2000 |