Plants small to robust, tufted or forming mats.  Corticolous, saxicolous or rarely terricolous.  Stems erect or creeping, variously branched, in section with central strand lacking.  Leaves erect-appressed or variously twisted when dry, spreading to squarrose when wet, variously ovate, oblong or lanceolate, occasionally undulate or rugose, unistratose, bistratose or rarely multistratose; apex variable, rarely fragile; margins generally entire but can be toothed; costa always present, single, percurrent to excurrent; upper laminal cells usually small, rounded hexagonal or rarely short rectangular, flat to bulging, incrassate, smooth, unipapillose to pluripapillose; basal laminal cells quadrate, rectangular or linear, incrassate, smooth, papillose or tuberculate, alar cells not differentiated.  Gemmae sometimes present.  Dioicous or autoicous.  Perigonia lateral or terminal, bud-like, leaves strongly differentiated, short, concave.  Perichaetia terminal on erect branches, leaves differentiated, oblong lanceolate to linear lanceolate.  Seta short to elongate, usually smooth, often twisted.  Capsules immersed to exserted, erect, ovoid to cylindric, smooth or ribbed, stomata superficial or immersed.  Operculum usually conic rostrate.  Peristome single, double, reduced or absent, exostome of 16 teeth, free or fused into 8 pairs or forming a continuous membrane, endostome often reduced, smooth or papillose.  Calyptra mitrate or cucullate, often relatively large, smooth or plicate, lobate or lacerate, naked or hairy.  Spores spherical, usually papillose, isosporous or anisosporous.

Plants in loose mats; primary stem prostrate with many erect to ascending branches; sporophytes usually produced on secondary branches

Plants tufted or in cushions; primary stem erect, simple or sparsely branched;

sporophytes produced on primary branches

Orthotrichaceae Part 1 – subfamily Macromitrioideae

The Orthotrichaceae subfamily Macromitrioideae is characterised by the prostrate primary stems with numerous erect secondary branches terminated by sporophytes, the dimorphism of stem and branch leaves and the large mitrate calyptrae. 

Plants medium sized, forming dense mats, brownish green to dull green.  Primary stems creeping with numerous short erect branches, densely tomentose.  Branch leaves contorted when dry and irregularly twisted around the stem, spreading when wet, oblong-ligulate to oblong-lanceolate, smooth, rugose or undulate, unistratose or often bistratose at apex; apex obtuse, mucronate or acute to acuminate, or ending in a fragile, deciduous subula; margins plane to undulate, entire; costa single, ending below apex to shortly excurrent; upper laminal cells quadrate-rounded to suboval, smooth or mammillate-bulging, basal laminal cells with a distinct margin of elongated cells, inner cells oblong to short rectangular-rounded.  Stem leaves differentiated in shape and size from branch leaves.  Sporophytes and gametangia not observed in East African material.

Plants medium sized, forming dense mats, brownish green to dull green.  Primary stems creeping, tomentose, with numerous erect branches, up to 2.5 cm tall.  Branch leaves contorted, typically twisted about stem when dry, spreading when wet, oblong-ligulate to oblong-lanceolate, 1.9–4.0 mm long, apex acute, often ending in a fragile subula which can be partially bistratose; margins plane to undulate, entire; costa single, ending just below or in apex; upper laminal cells quadrate-rounded to suboval, 8.4–14.0 µm, smooth, mammillate-bulging; basal laminal cells with a distinct margin 1/4–1/5 lamina length, forming 5–10 distinct rows, marginal cells short or long linear, smooth, inner basal laminal cells quadrate rounded, incrassate, bulging, often unipapillose, with an area of larger thin walled hyaline cells situated at basal corner of costa.  Stem leaves smaller, lanceolate, 1.0–1.2 mm long.  Sporophytes and gametangia not observed in East African material.

In Uganda known from Kabarole District, Masindi District and Bwindi NP.  Elsewhere in Africa recorded from: Central African Republic, Cape Verde, Gabon, Ghana, Guinea, Ivory Coast, Mauritius, Madagascar, Nigeria, Sierra Leone, Tanzania, Togo, Zaire and Zambia (O’Shea 2006).  Groutiella laxotorquata is currently considered restricted to Africa, however, it is a likely synonym of the widespread Groutiella tomentosa (Hornsch.) Wijk & Margad., which is known from America and Asia.   

In Uganda, G. laxotorquata has been collected from 1040–1480 m a.s.l., growing as an epiphyte on trunks and branches of trees. 

Plants slender, filiform, occasionally robust, forming mats, dark green to golden-brown.  Stems creeping with widely spaced branches.  Branch leaves closely appressed or occasionally slightly flexuose when dry, not contorted, erect-spreading to squarrose when wet, lanceolate to ovate-lanceolate, unistratose or bistratose; apex narrowly obtuse, acute to acuminate; margins plane, often recurved below, entire to crenulate; costa single, prominent, ending below apex; upper laminal cells rounded, quadrate, flat or bulging; basal laminal cells homogeneous, rounded, short rectangular to elliptic, bulging, often with tuberculae.  Stem leaves similar to branch leaves or differentiated.  Autoicous.  Perigonia terminal or lateral, leaves broadly ovate apiculate.  Perichaetia terminal on short branches, perichaetial leaves longer than branch leaves.  Seta elongate, smooth, < 10 mm long, ochrea present.  Capsule erect, urn cylindrical, lightly 8-ribbed or smooth; stomata superficial, at urn base.  Operculum conic rostrate.  Peristome double, single or absent, exostome of 16 teeth, usually reduced, endostome of 16 segments, usually forming a low membrane.  Calyptra large, mitrate, smooth or weakly plicate, naked to densely hairy.  Spores papillose, isosporous.

M. abyssinica

Plants medium sized to fairly robust, green to golden brown, forming loose mats.  Stems creeping, with numerous irregular branches, up to 4 cm tall.  Branch leaves in dry state loosely appressed, slightly twisted with apices spreading to reflexed, spreading when moist, lanceolate, 0.9–1.9 mm, unistratose; apex acuminate to acute, sharply pointed; costa ending below apex; upper laminal cells smooth, 8.4–19.6 µm, incrassate; basal laminal cells elliptic to rounded, bulging, often unipapillose.  Stem leaves similar or somewhat ovate lanceolate, 0.7–1.9 mm.  Autoicous.  Perigonia terminal on branches.  Perichaetial leaves 1.9–3.9 mm long.  Seta up to 10 mm long.  Capsule elliptic or oblong cylindrical, 1.5–2.0 mm long, smooth to lightly ribbed.  Peristome a low double membrane.  Calyptra large, mitrate, densely hairy.  Spores papillose, isosporous.  

In Uganda, Macrocoma abyssinica is locally common in the Ruwenzori Mts, Mt Elgon and Mt. Sabino.  It is restricted to Africa where it has also been recorded from Cameroon, Eritrea, Ethiopia, Kenya, Malawi, Rwanda, Socotra, Tanzania and Zaire (O’Shea 2006).

Macrocoma abyssinica is found at high altitudes and has been recorded from 2500–4100 m a.s.l. in Uganda.  It occurs as an epiphyte or occasionally on rocks and is locally common in Erica forests.

Macrocoma orthotrichoides (Raddi) Wijk & Margad.  Taxon 11: 221, 1962. (Fig. 3) 

Macrocoma tenuis subsp. tenuis (Hook. & Grev.) Vitt.  Rev. Bryol. Lichénol. 39: 217, 1973  (Fig. 4)

MACROMITRIUM Brid.  Musc. Rec. Suppl. 4: 132, 1819 [1818].  

Macromitrium sulcatum (Hook.) Brid.  Bryol. Univ. 1:319, 1826  (Fig 6)

(Macromitrium levatum Mitt. - fide Tixier 1989)

Plants medium sized to robust, green, yellowish-green to brownish-green.  Stems creeping with numerous bushy branches up to 4 cm tall, tomentose.  Branch leaves variously contorted and twisted when dry, erect spreading when wet, narrow lanceolate to oblong lanceolate, keeled, 2.2–4.7 mm long, unistratose, apex acute to acuminate, margins plane or occasionally undulate when lamina is broader, often denticulate above; costa ending below apex to slightly excurrent; upper laminal cells rounded irregular, incrassate, flat to bulging, arranged in longitudinal rows, 8.5–14.0 µm; basal laminal cells elongate, strongly incrassate, tuberculate, rarely smooth, with a distinct area of thin-walled hyaline cells situated at basal corner of costa.  Stem leaves smaller than branch leaves, ovate lanceolate, 0.8–1.4 mm.  Dioicous, producing dwarf male plants.  Perichaetia terminal, leaves shortly oblong-ovate to oblong-lanceolate, usually longer than branch leaves, 3.5–4.7 mm.  Seta 6–15 mm long, smooth.  Capsule ovate, ribbed, narrowed at mouth, < 2 mm.  Peristome double, exostome teeth fused forming a low membrane, endostome also a low membrane.  Calyptra mitrate, deeply lacerate, naked.  Spores papillose, anisosporous.

Macromitrium sulcatum is frequently collected from Uganda and is the most common member of the genus in sub-Saharan Africa.  It also occurs in Asia, extending from India as far east as Borneo (Eddy 1996). 

In Uganda, M. sulcatum has been recorded from 975–2700 m a.s.l., as an epiphyte on a range of different tree and shrub species, or more rarely growing on rocks.

SCHLOTHEIMIA Brid.  Musc. Rec. Suppl. 2: 16, 1812.

Plants medium sized, forming mats.  Stems creeping with erect bushy branches, often tomentose.  Branch leaves appressed and often spirally coiled around the stem when dry, erect-spreading when wet, ovate-oblong, ligulate, or oblong-acuminate, unistratose, often rugose; apex rounded-obtuse, acute, cuspidate or mucronate; margins plane or recurved below, entire; costa strong, often channelled, ending below apex to shortly excurrent; upper laminal cells rounded, incrassate, smooth, median cells often rhomboidal; basal laminal cells homogenous, narrowly rectangular, incrassate, pitted.  Stem leaves usually smaller than branch leaves, ovate-lanceolate, costa percurrent, shortly excurrent or aristate.  Dioicous, often producing dwarf male plants. Perichaetial leaves oblong-lanceolate to lanceolate.  Seta short to elongate, smooth.  Capsule exserted, erect, ovoid to ovoid-cylindrical.  Operculum short- to long-rostrate.  Peristome well developed, double, exostome of 16 teeth, reflexed when dry, papillose, endostome segments alternating with exostome teeth, shorter than exostome.  Calyptra large, mitrate, naked, lobed below.  Spores papillose, anisosporous.

Schlotheimia ferruginea (Bruch ex Hook. & Grev.) Brid. Bryol. Univ. 1: 743, 1826  (Fig 7)

(Schlotheimia rigescens Broth. -fide Wilbraham 2008)

Plants medium sized, forming mats, greenish brown to rusty brown.  Stems creeping with frequent secondary branches up to 2.5 cm long, tomentose. Branch leaves appressed and twisted around stem when dry, erect spreading when moist; broadly oblong-ovate to oblong-ligulate, 1.1–2.2 mm, unistratose, often rugose above; margins entire; apex rounded-obtuse, mucronate; costa stout, ending in or below mucronate apex; upper laminal cells rounded, 7.2–10.8 µm, incrassate, flat, smooth, medial cells rhomboidal; basal laminal cells narrow rectangular, incrassate, pitted.  Stem leaves ovate lanceolate, 0.6–1.4 mm, apex rounded-acute, costa usually shortly excurrent, occasionally ending in apex.  Dioicous, producing dwarf male plants.  Perichaetial leaves broadly oblong to oblong-lanceolate, 2.1–3.2 mm long.  Seta 2–7 mm long.  Capsule cylindrical, < 2 mm, smooth to weakly ribbed.  Peristome double, exostome teeth 16, ca. 400–450 µm, endostome segments 16–32.  Calyptra large, mitrate, < 3 mm, smooth, basally lobed.  Spores papillose, anisosporous. 

Frequently collected in Uganda and widespread across sub-Saharan Africa:  Angola, Kenya, Malawi, Rwanda, South Africa, Tanzania, Togo, Zaire, Zambia and Zimbabwe (Wilbraham 2008).  Elsewhere known from tropical Asia under the synonym Schlotheimia grevilleana Mitt. (Koponen & Enroth 1992. 

In Uganda, S. ferruginea occurs at 1040–1540 m a.s.l., as an epiphyte on trees or occasionally growing on rocks. 

Plants medium sized, forming mats, greenish brown to rusty brown.  Stems creeping, with frequent secondary branches up to 3 cm tall, tomentose.  Branch leaves appressed and twisted to spirally twisted around stem when dry, erect spreading when moist, oblong lanceolate, attenuate, 1.4–2.7 mm; unistratose, occasionally rugose above, apex acute to cuspidate, occasionally fragile; costa ending below apex or extending into cuspidate point; upper laminal cells rounded, 7.0–12.0 µm, incrassate, flat, smooth, medial cells rhomboidal; basal laminal cells narrow rectangular, incrassate, pitted.  Stem leaves ovate to ovate-lanceolate, 0.8–2.2 mm, apex acute to acuminate, costa ending below apex or extending into tapering point.  Dioicous, producing dwarf male plants.  Perichaetial leaves broadly oblong to oblong-lanceolate, 1.9–3.2 mm.  Seta 1.5–7.0 mm long.  Capsule cylindrical, < 3 mm long, smooth to weakly ribbed.  Peristome double, exostome teeth 16, approx. 330–440 µm, endostome segments 16–32.  Calyptra large, mitrate, < 3 mm, smooth, basally lobed.  Spores papillose, anisosporous.

Schlotheimia percuspidata has been frequently collected in Uganda.  It is restricted to sub-Saharan Africa where it is also known from Kenya, Malawi, South Africa, Tanzania and Zimbabwe (Wilbraham 2008). 

In Uganda, S. percuspidata has been recorded from altitudes of 1060–1522 m a.s.l., growing as an epiphyte on trees or occasionally on rocks.

Figure 8.  Schlotheimia percuspidata.  (a) habit (dry); (b) capsule with calyptra; (c) branch leaves; (d) stem leaves; (e) perichaetial leaf; (f) basal laminal cells; (g) upper laminal cells; (h) branch leaf apex; (i) cross-section mid-leaf of branch leaf.  (a–i) Drawn from O’Shea U2802a (BM). 

I am grateful to G.& S. Miehe, K. Wesche, H. Matcham, C.C. Townsend and the curators at the herbaria of E, G, and PRE for loan of specimens.  I would like to thank Brian O’Shea for commenting on the manuscript for this paper. 

Joanna Wilbraham, Botany Department, The Natural History Museum, Cromwell Road, London, SW7 5BD, U.K.  E-Mail:  j.wilbraham@nhm.ac.uk