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SPLACHNACEAE

(B.J. O'Shea)

Plants somewhat small to medium sized, gregarious or forming loose to dense tufts, often lustrous green or reddish-brown. Stems erect, few to several branched by innovations, radiculose below, occasionally tomentose; central strand present. Leaves distant to crowded, often comose distally, rather lax, occasionally crispate when dry, ovate-lanceolate, oblong or obovate to spathulate, apex apiculate, acuminate, acute or obtuse, base occasionally decurrent; margins entire or bluntly to sharply serrate or ciliate, limbate or elimbate; costa single, subpercurrent to long excurrent; laminal cells rather large, smooth, median cells rhomboidal, hexagonal or irregularly rectangular; lower and basal cells laxly oblong or rectangular; alar region undifferentiated. Propagula apparently absent. Autoicous or dioicous. Perigonia on lateral short branches; paraphyses clavate. Perichaetia terminal, leaves little differentiated. Seta somewhat short to more commonly elongate, rather stout, smooth to scabrous. Capsule erect, urn mostly short or long cylindrical; hypophysis lacking or when present inflated and elongate or obovoid, sometimes as long or longer than urn; annulus appearing absent. Operculum conic or convex-apiculate. Peristome single, teeth 16 and united in 8 pairs or initially 4 pairs at base and distally divided, erect or reflexed, mostly variously papillose. Calyptra mitrate and lobed at base, naked to roughened-papillose or ciliate. Spores spherical, smooth or variously papillose.

Discussion. The Splachnaceae contain seven genera and about 60 species, widely distributed in boreal and temperate regions, and in the tropics confined to the highlands; in Africa four genera and 12 species. The Splachnaceae are the only family of mosses known to exhibit entomophily, usually involving those plants found growing on dung or carrion. The studies summarised by Koponen (1990) have shown that various species in several genera produce volatile compounds, emitting an odour from the stomata that attracts flies and assists in the dispersal of spores (not unlike that of many members of the family Araceae). Most of the studies involve taxa from the Northern Hemisphere, and it is not clear whether tropical Splachnaceae are also entomophilous, and only Tetraplodon of the African genera has been noted as growing on dung (but see also Splachnum treatment below).

Literature. Koponen, A. 1977. Tayloria subgen. Pseudotetraplodon. subgen. nov., and new combinations in Brachymitrion, Moseniella and Tayloria (Splachnaceae, Musci). Annales Botanici Fennici 14: 193-196. Koponen, A. 1982. On the structure and function of the peristome in Splachnaceae. Journal of the Hattori Botanical Laboratory 53: 73-98. Koponen, A. 1983. Studies on the generic concept in the classification of the moss family Splachnaceae. Academic Dissertation, University of Helsinki. Koponen, A. 1990. Entomophily in the Splachnaceae. Botanical Journal of the Linnean Society 104: 115-127. Koponen, A., Koponen, T., Pyysalo, H., Himberg, K. & Mansikkamäki, P. 1990. Composition of volatile compounds in Splachnaceae. Pages 449-460. In: H. D. Zinsmeister & R. Mues, Bryophytes: Their Chemistry and Chemical Taxonomy. Oxford: Clarendon Press. Koponen, T. & Weber, W.A. 1972. A revision of African Tayloriae (Splachnaceae), including Bryomnium. Annales Botanici Fennici 9: 126-134.

Brachymitrion Taylor

Four species in Africa (Gulf of Guinea islands, Cameroon, Tanzania and Madagascar), with six species in the genus.

Plants medium sized to rather large, forming loose tufts, glossy or somewhat lustrous green, yellowish-green or golden. Stems erect, few branched, densely tomentose; in cross-section angular (5-sided), hyalodermis present, central strand present; rhizoids reddish-brown, smooth or papillose. Leaves crispate or contorted when dry, erect-spreading when wet, obovate to spathulate, 4-6 mm long, apex broadly acute or obtuse and apiculate, base short to long decurrent; margins plane, bluntly serrate or ciliate, limbate or not; costa subpercurrent to ending well below apex; laminal cells smooth, median cells short hexagonal to rhomboidal; lower and basal cells long rectangular; marginal cells forming a weak border with a single row of cells or distinct golden coloured border of 4-6 rows, cells fusiform to rhomboidal. Autoicous. Seta elongate, 2-20 mm long, smooth, twisted or not. Capsule erect, urn cylindrical, 1.5-4.5 mm long, mouth somewhat flared when deoperculate, hypophysis absent; neck short; exothecial cells thick-walled; stomata at base of urn, superficial. Operculum short rostrate. Peristome single, teeth 16, united at apex, reticulate or reticulate-striate, occasionally with few perforations along median line. Calyptra mitrate, ciliate or scabrous. Spores reticulate.

Habitat. Information on the genus is limited, but it has been found on rocks and stones, epiphytic on tree trunks and on decaying logs, in montane forests, 950-2890 m.

Discussion. The genus is characterized by ciliate or distinctly bordered leaf margins, apices of peristome teeth united in pairs, and a ciliate or scabrous mitrate calyptra. Koponen & Weber (1972) provides a key for B. jamesonii and B. moritzianum (= B. thomeanum), with B. immersum described in Goffinet (1999) and B. pocsii in Koponen (1975). Mt. Cameroon is the prime African locality for this genus, with 3 of the 4 species.

Literature. Goffinet, B. 1999. Brachymitrion immersum (Splachnaceae, Musci) a new species from Cameroon. Bryologist 102: 108-111. Koponen, A. 1975. Tayloria pocsii, spec. nova (Musci, Splachnaceae) from Mt. Kilimanjairo, Tanzania. Annales Botanici Fennici 12: 22-24 [= Brachymitrion pocsii (A.Kop.) A.Kop.]. Koponen, T. & Weber, W.A. 1972. - see family ref.

Splachnum L. ex Hedw.

One species in Africa, Splachnum adolphi-friederici Broth. known from D.R. Congo and Uganda; a genus of nine species associated with cool, moist temperate regions.

Plants forming dense tufts, glossy pellucid green. Stems to ca. 4 cm or more tall, few branched, tomentose below; central strand present. Leaves smaller below, distally crowded and larger, ± crispate or contorted when dry, erect-spreading when wet, elliptical-lanceolate or oblanceolate, 3.0-5.5 mm long, to 2 mm wide, distally folded, apex narrowing into an apiculus; margins plane, entire to sharply serrate distally; costa short excurrent; median cells large, hexagonal to hexagonal-fusiform; lower and basal cells long rectangular; alar region undifferentiated; marginal cells oblong-rectangular. Autoicous. Perigonia on short branches; leaves with an oval base and distal wide-spreading, lanceolate limb. Perichaetia terminal; leaves similar. Seta elongate, 5-40 mm long, slender, flexuose or not, pale whitish-green to pink or dark bright red, smooth, twisted when dry. Capsule erect, short to long exserted, differentiated between a short urn and inflated neck (hypophysis), urn cylindrical, 0.6-1.5 mm long, brown; exothecial cells strongly collenchymatous, oblate-rectangular or subquadrate; hypophysis pyriform or only slightly inflated, 1.5-6.0 mm long, to 4 mm wide, pale pink or red; stomata on distal hypophysis, superficial; columella often shortly exserted when dry. Operculum convex- or conic-apiculate. Peristome teeth fused in 8 pairs, papillose, reflexed when dry. Calyptra mitrate-campanulate, ca. 1.2 mm long. Spores spherical or oval, smooth or lightly papillose.

Habitat. On dung or soil probably previously associated with dung; mid to high open montane areas, 3000-3900 m.

Discussion. The genus is readily recognized by the inflated hypophysis, combined with apiculate, elliptical-lanceolate or oblanceolate leaves, often weakly bordered margins, and peristome teeth fused into 8 pairs. Splachnum adolphi-friederici Broth. appears to have been collected only four times (Porley in Eggers et al. 2001), most recently in the Virunga mountains (Uganda), and three times in the Rwenzori mountains. Porley (op. cit.) notes that one of the BM specimens suggests a similarity to the boreal S. ampullaceum, although on the specimens seen, the African collections appears to have apiculate leaves (rather than long-acuminate as in S. ampullaceum), and the plants are significantly taller. The Uganda specimen was collected from a decaying log, but might have been growing on animal dung.

Literature. Eggers, J., Stevenson, C.R., Porley, R.D. & Stech, M. 2001. New bryophyte taxon records for tropical countries IV. Tropical Bryology 20: 97-100.

Tayloria Hook.

Six species in Africa; about 38 species worldwide, rather widely distributed but concentrated in the highland tropics and subtemperate regions.

Plants small to medium sized, forming tufts, glossy green to reddish-brown. Stems erect, simple or few branched, usually tomentose below; in cross-section epidermis small, inner cells large and thin-walled, central strand present; rhizoids smooth to papillose. Leaves mostly crispate or contorted when dry, erect-spreading when wet, ovate-short lanceolate, elliptical to obovate or spathulate, apex broadly acuminate, acute or obtuse; margins plane to reflexed below, entire, bluntly serrate or crenulate distally, elimbate; costa 3/4 -4/5 lamina length or subpercurrent; upper and median cells large and smooth, hexagonal to rhomboidal; basal cells rectangular, rather lax. Autoicous. Perichaetia terminal, leaves similar to stem leaves. Seta rather short to elongate, twisted or not, smooth or scabrous. Capsule emergent to long exserted, erect, dark red to reddish-black, urn short cylindrical; exothecial cells oblate, thick-walled; hypophysis short (usually equal to or shorter than urn), cells elongate, thin-walled, stomata in distal half, superficial. Operculum not observed. Peristome single, teeth 8 or 16, papillose, reflexed when dry. Calyptra not observed. Spores spherical, appearing smooth to lightly papillose.

Habitat. Usually epiphytic (including forest trees, bamboo, Ericaceae and Dendrosenecio), but also on soil and humus, occasionally on dung; open montane forests and afromontane areas, 500-3700 m.

Discussion. The genus is characterized by the obovate, spathulate to elliptical or broadly short lanceolate leaves, elimbate, entire to toothed margins, smooth to occasionally papillose seta, cylindrical capsule, rather narrow and short hypophysis, and papillose, 8 or 16 toothed peristome. Koponen & Weber (1972) provides a key, with additional information on T. orthodonta in De Sloover (1973).

Literature. Boecker, M. 2001. Taxonomic results of the BRYOTROP expedition to Zaire and Rwanda 33. Splachnaceae, Tayloria. Tropical Bryology 20: 71-72. De Sloover, J.L. 1973. Note de bryologie africaine. 1. Brachydontium, Atractylocarpus, Amphidium, Rhabdoweisia, Tayloria, Rhacocarpus, Trachypodopsis. Bulletin du Jardin Botanique National de Belgique 43: 338-348. Koponen, T. & Weber, W.A. 1972. - see family ref.

Tetraplodon Bruch, Schimp. & W.Gümbel

A single species in Africa, T. mnioides (Hedw.) Bruch, Schimp. & W.Gümbel, known from Kenya, Tanzania, Uganda and D.R. Congo (Zaire); about five species in the genus, primarily of the Northern Hemisphere, but also in mountains throughout the tropics.

Plants medium sized, forming dense compact tufts, pale green to yellowish-green. Stems erect, to 3 cm or more tall, few branched, densely tomentose; central strand well developed. Leaves crowded, erect to erect-spreading, oblong- to obovate-lanceolate, 4.0-5.5 mm long, to 1.8 mm wide, deeply concave, apex narrowly acuminate, ending in a long hyaline subula; margins entire; costa ending in subula; laminal cells smooth, median cells oblong, rectangular- to hexagonal-rounded; basal cells long rectangular, lax. Autoicous. Perichaetia terminal, leaves ± larger than stem leaves. Seta elongate, to 30 mm long or more, stout, smooth. Capsule erect, urn short cylindrical, to 1.5 mm long, hypophysis narrowly elliptical, ca. 2 times longer than urn. Operculum conic. Peristome single, teeth fused into 4 pairs at base, and distally becoming 2-paired, reflexed when dry, outer surface papillose, inner surface smooth. Calyptra mitrate, smooth and naked. Spores spherical, smooth.

Habitat. On rocks, burnt ground, fallen trees and on carnivore dung, usually containing the remains of small mammals. Subalpine ericaceous heath and alpine semi-desert, 3000-4250 m.

Discussion. The genus is distinguished by the densely compact tufted plants, oblong-lanceolate to oblanceolate leaves, percurrent costa ending in a subula, and 8 peristome teeth, papillose on the outer surface, smooth on the inner.

accepted 17.04.2000