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Mosses and Liverworts of Uganda
GymnomitriaceaeBy J. Vána (illustrations by M. C. Watling)Plants forming dense mats or cushions, rarely intermixed between other bryophytes (e.g. Grimmia, Andreaea). Shoots mostly 5-80 mm high and 0.1-3.5 mm wide, erect or ascending, rarely prostrate. Stems mostly differentiated into 1(-2) cortical layers of smaller thick-walled cells, sometimes also with thin-walled hyalodermis of larger cells, and larger medullary cells. Branching uncommon, mostly lateral-intercalary, sporadically terminal, dorsal-intercalary or ventral-intercalary. Rhizoids scattered. Leaves mostly transversely, rarely subtransversely succubously inserted, alternate, lateral merophytes interlocking in the dorsal face of the stem, mostly bilobed, rarely retuse on unlobed or trilobed; leaf margins and apices decolorate in many taxa. Underleaves lacking or only exceptional in primitive taxa, very small. Leaf cells relatively small, mostly only 8-30 µm, walls thin or thickened, trigones small, large to bulging. Cuticle smooth or papillose. Oil-bodies mostly 2-3 per cell, spherical to ovoid, colourless, granular to papillose. Asexual reproduction unknown. Mostly dioicous or paroicous plants. Androecia terminal, becoming intercalary or subgynoecial, spicate. Antheridia 1-4 per bract, ovoid, with long biseriate stalk. Gynoecia terminal. Perianth present or reduced to tubular structure, scales or laciniae, in some species completely lacking; perigynium present or absent. Sporophytes uncommon. Seta short or longer, composed of numerous cell rows. Capsule spherical or nearly so, with 2-3-stratose wall; epidermal cells with nodular, inner layer cells with incomplete or complete semiannular thickenings. Spores mostly granular, elaters 2- (rarely 3-4)-spiral.
Apomarsupella R.M.Schust., J. Hattori Bot. Lab. 80: 79, 1996 Plants mostly forming blackish or reddish patches, sometimes nitid. Shoots medium sized, mostly 10-50 mm high and 1.2-2 mm wide. Stems mostly erect, simple or sparsely branched, without hyalodermis and with hardly defined 2-3 cortical layers of smaller cells; branching predominantly antical-intercalary, rarely lateral-intercalary, stoloniferous branches present. Rhizoids very few, mostly restricted to base of stem, scattered. Leaves contiguous to slightly imbricate, transversely inserted, erect spreading, concave, ovate to obovate, decurrent, basally sheathing, bilobed to 0.2-0.5 their length; margin somewhat revolute. Lobes rounded to subacute, sinus sharp to obtuse. Underleaves absent. Leaf cells small, 15-25 × 10-15 µm, basal cells mostly elongated to 40 µm. Oil-bodies 2-3 per cell. Dioicous. Androecia terminal, becoming intercalary, antheridia 1-3 per bract. Gynoecia terminal, with intercalary innovations. Bracts in 2-3 pairs, innermost pair erect, connivent, shallowly bilobed. Only delicate calyptra present; perianth and perigynium totally absent. Seta massive, about 8-12 cells wide. Capsule globose, with (2-)3-stratose wall; cells with nodulose thickenings. Spores small, 10-12 µm; elaters 2-spiral, sometimes 1-spiral on the end and 3-4-spiral in the middle. Apomarsupella africana (Steph. in Bonner) R.M.Schust., J. Hattori Bot. Lab. 80: 91, 1996 (Fig. 1)
Known only from wet rocks and stones in the alpine zone of the Rwenzoris: collected at 4300 m not far S. of Scott Elliot Pass by O. Hedberg in 1948, and at 4420 m on the E. side of Mt Stanley by E. Esterhuysen in 1956. Another Hedberg specimen, from Mt Muhavura, belongs to Marsupella subintegra. In Africa also known from D.R. Congo, Kenya, Rwanda and Tanzania, elsewhere known from Chile, Guatemala, Mexico and Venezuela.
Gymnomitrion Corda in Opiz, Beiträge zur Naturk. 651, 1828 Plants forming compact and pure cushions, rarely only separate shoots in patches of other bryophytes. Shoots small to medium sized, mostly 5-20 mm high and 0.2-0.7 mm wide, terete or dorsiventrally compressed, julaceous or filiform. Stems erect or ascending, with cortical cells slightly thick-walled, without hyalodermis. Branching frequent to infrequent, exclusively lateral-intercalary, some branches stoloniform or flagelliform. Rhizoids scattered from stolons or bases of stems. Leaves subtransversely to nearly transversely inserted, slightly succubous, usually closely erect-appressed, rarely loosely-imbricate, concave, mostly broadly ovate and shallowly to moderately bilobed, rarely unlobed, with decolorate margins; lobes rounded, acute or acuminate-piliferous. Underleaves absent to very small and then connate at base with one leaf. Leaf cells with rounded lumens and large to bulging trigones, or more uniformly thick-walled, with trigones absent or very small. Cuticle smooth or papillose. Oil-bodies mostly 2-3 per cell, finely granular, absent in marginal and apical cells. Dioicous. Androecia becoming intercalary, antheridia 2-3 per bract. Gynoecia terminal, bracts in several pairs, larger than vegetative leaves; apex of gynoecial shoots sometimes clavate. Perianth absent, replaced by irregular laciniae or scales; perigynium absent. Calyptral perigynium ± distinct, sometimes with sterile archegonia on calyptra. Capsule spherical, with 2(-3)-stratose wall with nodular thickenings. Elaters 2(-4)-spiral. Gymnomitrion laceratum (Steph.) Horik., Acta Phytotax. Geobot. 13: 212, 1943 (Fig. 2)
Collected only once in the Rwenzoris, on steep west-facing rock at 3900 m in the Mijusi Valley, by O. Hedberg in 1948. Known from other high mountains in Africa in D.R. Congo, Kenya, Natal, Réunion, Rwanda, South Africa and Tanzania. Also known from Bolivia, Japan, Mexico, Nepal, Peru, Russia (Altai Mts), U.S.A. (Tennessee) and Venezuela. Gymnomitrion laceratum. a, Shoot; b-h, leaves; i, lobe cells; j, mid-leaf cells. TANZANIA
Marsupella Dumort., Comment. Bot. 114, 1822 Plants forming dense mats of mostly erect shoots. Shoots mostly 5-80 mm high and 0.1-3 mm wide, green, reddish or blackish. Stems mostly erect, with thick-walled cortical cells and sometimes also with large-celled hyalodermis, simple or sparsely branched; branching mostly lateral-intercalary, never antical-intercalary, stoloniform branches sometimes present. Rhizoids scattered from basal portions of shoots, relatively rare. Leaves nearly transversely inserted, alternate, not decurrent, erect-spreading to widely spreading, concave to canaliculate, simply bilobed or unlobed, with entire-margined, mostly equal lobes. Underleaves absent. Leaf cells mostly small, with large to bulging trigones. Cuticle mostly smooth. Oil-bodies 2-5 per cell, granular, in all leaf cells. Monoicous (paroicous) or dioicous. Androecia terminal, becoming intercalary, antheridia 1-6 per bract. Gynoecia terminal, bracts in 2-3 pairs larger than vegetative leaves. Perianth medium sized, obconic to ovate, contracted to the mouth, connate with the bracts and forming low erect or rarely pendent perigynium; sometimes small to reduced on very low cylindrical structure. Calyptra delicate. Capsule globose to slightly ovoid, with 2-3-stratose wall; outer layer with nodular thickenings, inner layer with semiannular thickenings. Spores small; elaters 2 (-4)-spiral.
Marsupella emarginata (Ehrh.) Dumort., Comment. Bot., p. 114, 1822 (Fig. 3)
Known only from moist steep rocks on Mt Muhavura where it has been collected twice: at 3900 m on the N.W. slope by O. Hedberg in 1948, and at 3200 m on the N. slope by K. A. Lye in 1969. Also known from other high African mountains in D.R. Congo, Rwanda and Tanzania. Widely distributed in the Holarctic and on high mountains in Borneo, Colombia, Mexico, Philippines and Sumatra. Marsupella emarginata. a, Shoot; b-k, leaves; l, mid-leaf cells. Pócs & Ochyra 88152/S (BR) TANZANIA (apologies for missing area at the top). -------------------- Marsupella subintegra S.W.Arnell, Ark. Bot., ser. 2, 3/16: 545, 1956 (Fig. 4)
Collected only twice, in the Rwenzoris on steep moist alpine rocks, at 4000 m near the bottom of the Mijusi Valley, and at 3900 m on the W. slope of Mt Muhavura, both by O. Hedberg in 1948. In Africa also known from Malawi, Réunion and Rwanda; elsewhere known from Borneo, Nepal, Papua New Guinea and Sumatra. Marsupella subintegra. a, Shoot; b-k, leaves; l, mid-leaf cells. TANZANIA ---------------------------- Excluded taxa:
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Plants in reddish brown patches dense patches. Shoots 10-30
mm long and 1.2-2 mm wide, simple or sporadically
dorsal-intercalary branched, with lateral-intercalary subfloral innovations. Stems with
hardly differentiated
cortical cells. Rhizoids rare to absent. Leaves transversely
inserted, imbricate, decurrent on both sides, ovate, bilobed to 0.25-0.3
of the length, margin slightly revolute,
base sheathing. Lobes obtuse to subacute, sinus
acute, somewhat gibbous. Leaf
cells 10-15 µm, basal to 20 × 15 µm, walls thick, trigones
large to bulging. Cuticle smooth. Dioicous. Androecia terminal
to intercalary, bracts ventricose, densely imbricate, antheridia 1-2 per
bract. Gynoecia terminal,
innermost bracts erect, concave, larger than vegetative leaves, bilobed
to 0.2-0.25 their length. Perianth and perigynium absent. Capsule sphaerical,
with 3-stratose wall. Spores 10-12 µm, papillose, elaters 2-spiral, 60-90 × 6-8 µm.
Plants greyish-green, whitish-green,
glaucous to pale brownish, in dense tufts, very small, 4-10 mm high and
0.2-0.4 mm wide, julaceous
or filiform. Shoots ascending or erect, rigid. Stems 8-10
cells thick, cortical cells hardly differentiated, thin-walled with slightly
thickened angles. Rhizoids relatively
frequent. Leaves loosely imbricate-squarrose,
erecto-patent, with decolorate margins, ovate to oblong-ovate, bilobed
to 0.3-0.45 their length. Lobes acute, 10-15
cells wide at base, sinus acute, margins somewhat recurved. Underleaves sporadically
present, small. Leaf cells thick-walled, mostly
in rows, rectangular to quadrate, 15-22 × 12-16 µm, without
trigones. Cuticle smooth. Oil-bodies not
observed in African collections. Dioicous. Androecia terminal,
becoming
intercalary, of 5-7 pairs of bracts. Gynoecia terminal,
clavate bracts larger than vegetative leaves, irregularly dentate, innermost
bracts
deeply laciniate. Perianth and perigynium absent. Capsule spherical. 
Plants in green, reddish brown
to brownish patches. Shoots (10-)20-50 mm
high, 1.6-2.4 mm wide, erect, simple or very sporadically branched, branching
mostly in form of subfloral innovations. Stems with
one layer of thicker-walled cells larger than 3-4 intracortical layers
with much thick-walled cells.
Rhizoids rare, colourless to vinaceous. Leaves contiguous,
subimbricate, nearly transversely
and markedly pectinately inserted and oriented, rotundate, to 0.2-0.3
their length bilobed, sinus acute to obtuse, lobes obtusely pointed
to subacute.
Leaf cells (15-)17-30 µm, walls thin,
trigones large. Oil-bodies 2-3 per cell,
finely granular. Dioicous. Androecia terminal,
becoming intercalary,
bracts in 3-5(-10) pairs, antheridia 3-5 per bract. Gynoecia terminal,
often with innovations. Perianth short, tubular,
irregularly lobed, nearly all hidden
within bracts; perigynium relatively high. Capsule spherical,
capsule wall 2-3-stratose. Spores 10-13 µm,
verrucose; elaters 2(-3)-spiral.
Plants in brown to reddish,
dense patches. Shoots 10-15 mm long and 1.2-2
mm wide, simple or sporadically lateral-intercalary branched. Stems with
1-2 layers of deeply colored smaller cortical cells. Rhizoids rare,
colourless to purplish. Leaves transversely
inserted, concave to spoon-shaped, antically decurrent, rounded to ovate,
retuse to shallowly (to 0.1 of the length) bilobed,
rarely unlobed, postical margin ± reflexed; base sheathing. Leaf
cells very small, 8-20 µm, basal to 30 µm,
walls thin to somewhat thickened, trigones large. Cuticle smooth. Dioicous. Androecia terminal,
bracts in 3-7 pairs, antheridia 2-4 per bract. Gynoecia terminal,
with some pairs of bracts larger than the vegetative leaves, the innermost
bracts smaller,
basally connate.
Perianth absent, perigynium weakly developed. Capsule spherical,
capsule wall bistratose, outer wall with nodular thickenings. Spores 10-12 µm,
elaters 2(-3)-spiral.