Flora of tropical East Africa - Marsileaeceae (2003) (Flora of Tropical East Africa)

FLOR A OF

TROPICAL EAST AFRICA prepared at the Royal Botanic Gardens, Kew in cooperation with the East African Herbarium, the National Herbarium of Tanzania and the Herbaria of Makerere University and Dar es Salaam University

EDITOR

H.J. BEENTJE, M.Sc., Ph.D., F.L.S. SUB-EDITOR

S.A. GHAZANFAR, M.Sc., Ph.D.

MARSILEACEAE BY

E. LAUNERT, Dr. rer. nat.

PUBLISHED ON BEHALF OF THE EAST AFRICAN GOVERNMENTS by

A.A. BALKEMA PUBLISHERS/LISSE/THE NETHERLANDS A member of Swets & Zeitlinger Publishers and obtainable from the addresses listed on the back of the cover 2003 ISBN 90 5809 414 6

FLORA OF TROPICAL EAST AFRICA MARSILEACEAE E. LAUNERT* Small aquatic or semi-aquatic ferns with a creeping, branched, solenostelic rhizome. Fronds circinnate when young, simple or with 2 or 4 opposite leaflets borne terminally on a long stipe; veins dichotomously branched, anastomosing. Sporangia contained in closed sporocarps which are inserted on short (or in two species, up to 2 cm) pedicels on the stipe (usually at the very base). Spores of 2 kinds, solitary megaspores and numerous microspores (contained in megasporangia and microsporangia respectively). Family of 3 genera, only one of which occurs in tropical Africa. Pilulariaceae has sometimes been kept separate.

MARSILEA L., Sp. Pl.: 1099 (1753) & Gen. Pl. ed. 5: 485 (1754); Launert in Senck. Biol. 49: 273–315 (1968) & in Garcia de Orta, Sér. Bot. 6: 119–140 (1985) Small aquatic or semi-aquatic ferns with a creeping, branched solenostelic rhizome. Fronds circinnate when young, with 4 leaflets in a terminal cluster, arranged symmetrically cross-wise at the apex of the stipe, floating in submerged plants, otherwise erect or decumbent. Leaflets herbaceous, obtriangular to obovate, rarely narrowly triangular, with the outer margin entire, sinuate, crenate or lobate; veins dichotomously branched, anastomosing, often with interstitial suberose streaks on the lower surface (in submerged plants), sometimes with sclerenchymatic interstitial pellucid streaks (M. coromandelina, M. distorta, M. fenestrata). Sporangia contained in closed sporocarps which are inserted on short (or in two species, up to 2 cm) pedicels on the stipe (usually at the very base); one or two teeth often present at base, near the insertion point of the pedicel. Spores of 2 kinds, solitary megaspores and numerous microspores (contained in megasporangia and microsporangia). A cosmopolitan genus of about 70 species. Many African species are adapted to seasonal changes in which a wet season is followed by a period of drought. As entirely different fronds are often produced in each phase, it is no small wonder that in the past botanists have based new taxa on such seasonal forms. Sporocarps are essential for determination. Numerous sterile specimens have been collected but cannot be determined. The spellings Marsilia and Marsiliaceae have been used by a few workers.

* Address of the author: c/o Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB, England. This account is based entirely on the published papers and determinations of E. Launert. Preliminary editing into Flora format and addition of references, geography etc. was carried out by B. Verdcourt

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MARSILEACEAE

MARSILEA

1. Pedicel branched dichotomously from a common base, or virtually absent; sporocarps (3–)5–25 in dense clusters · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2 Pedicels free from each other or only fused at the base, never branched dichotomously (rarely very short to almost absent in M. nubica); sporocarps solitary or in groups of 2–3(–5), or crowded in M. minuta · · · · · · · · · · · · · · · · · · · · · · · · 3 2. Sporocarps without a marked pedicel situated on a short blackish stout conical base, 3–6 with their bases united forming a dense cluster on the rhizome at the very base of the stipe with the individual sporocarps in a vertical or semi-vertical position · · · · · · · · · · · · · · · · 8. M. fadeniana Sporocarps with marked pedicels which are adnate and dichotomously branched from a common pedunclelike base · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6. M. botryocarpa 3. Sporocarps 4 to many, characteristically arranged in a single or double row along the stipe · · · · · · · · · · · · · · · · · · · · · · · · · · · · 4 Sporocarps not arranged in a row along the stipe, if attached to the stipe above its base then either solitary or in pairs or in branched clusters · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 5 4. Sporocarps narrowly elliptic in dorso-ventral cross-section, the long axis usually at a right angle to the pedicel, with 2 prominent teeth · · · · · · · · · · · · · · · · · · · · · · · · · · 7. M. minuta Sporocarps obliquely semi-elliptical or biscoctiform1 in dorso-ventral cross-section, the long axis usually at an angle with the pedicel, with weak or obsolete inferior tooth and very shortly conical superior tooth · · · · · · 11. M. megalomanica 5. Leaflets with pellucid interstitial streaks visible by transmitted light · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 6 Leaflets without pellucid streaks (may have brownish suberose non-pellucid stripes) · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 7 6. Superior tooth of sporocarps absent or indicated only as a brownish spot; inferior tooth prominent; sporocarps usually permanently densely brownish tomentose, usually crowded at the base of the stipe; pedicel pigtaillike, curved or rarely straight · · · · · · · · · · · · · · · · · · 4. M. distorta Superior tooth always present, obtuse or acute; inferior tooth obtuse; sporocarp appressed pilose, gradually becoming glabrous; pedicel straight or gently curved 5. M. coromandelina 7. Sporocarps black, usually glossy with the outer layer of epidermis usually becoming detached and peeling off in irregular papery pieces · · · · · · · · · · · · · · · · · · · · 3. M. nubica Sporocarps brown or rarely blackish, not glossy, the outer layer of epidermis never detached (almost black in S. minuta) · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 8 8. Sporocarps with hairs of 2 kinds, erect cylindrical hairs and appressed flattened hairs; cells of the erect hairs collapsed in dried specimens thus giving the sporocarp a farinose appearance · · · · · · · · · · · · · · · · · · · · · · · 9. M. farinosa Sporocarps only with laterally attached flattened hairs · · · · · · · · · · · · · · · · · 9 9. Pedicels growing horizontal or more often downwards, burying the sporocarp in the ground · · · · · · · · · · · · · · · · · · · · · · · · · · 10 Pedicels growing upright or ascending · · · · · · · · · · · · · · · · · · · · · · · · · · · 12

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biscoctiform: shaped like a dog biscuit, oblong with the ends slightly wider and rounded

MARSILEA

MARSILEACEAE

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10. Sporocarps always tomentose even when fully mature, usually densely crowded; superior tooth completely absent or present as a dark circular spot only; pedicels slender, repeatedly curved, pigtail-like · · · · · · · · · · · 4. M. distorta Sporocarps appressed hairy, or villous, usually becoming glabrous with age; superior tooth always present; pedicels straight or gently curved · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 11 11. Sporocarps 3.8–5.5 mm long, 3–4.5 mm wide, up to 3.8 mm thick; superior tooth distinct, acute or subacute; pedicels (6–)8–15 mm long, slender, gently curved · · 1. M. gibba Sporocarp 3–3.5 mm long, 2.2–2.8 mm wide, up to 2.7 mm thick; superior tooth inconspicuous, usually obtuse; pedicels 2–5 mm long, rather stout, straight or sharply curved · · · · · · · · · · · · · · · · · · · · · · · · · · · · 2. M. subterranea 12. Pedicels 2–3(–4) united at their bases to a varying degree 7. M. minuta Pedicels always free (sometimes crowded) · · · · · · · · · · · · · · · · · · · · · · · · 13 13. Both sporocarp teeth present, often different in size · · 5. M. coromandelina Only the superior tooth of the sporocarp developed, obtuse or acute, the inferior completely absent or represented by only a very shallow hump · · · · · · · · · 10. M. macrocarpa 1. M. gibba A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1870: 745 (1871); Hieron. in V.E. 2: 66 (1908) (as Marsilia); Tardieu & Alston in Mém. I.F.A.N. 50: 16, t. 2, figs. 7–9 (1957); Alston, Ferns W.T.A.: 25 (1959); Launert in Senck. Biol. 49: 280 fig. 6 (1968) & in F.A.C., Marsileaceae: 6, t 1/F (1975); Pic. Serm. in B.J.B.B. 53: 241 (1983); Launert in Garcia de Orta, Sér. Bot. 6: 123, t.1, fig. 4 (1985); Schippers in Fern Gaz. 14: 212 (1993); Faden in U.K.W.F. ed. 2: 37 (1994). Type*: Sudan, Djur, Agade, Schweinfurth 2462 (B!, lecto., BM!, FR!, M!, iso.) Loosely caespitose plant; rhizome slender, repeatedly branched, terete or furrowed, glabrous or very scattered pilose, sometimes somewhat villous at the nodes; internodes 0.5–15 cm long. Stipes 3–15(–20) cm long, rather slender, glabrous or rarely sparsely pilose. Leaflets olive-green to dark green, broadly obtriangular or rarely narrowly obtriangular, 5–16 mm long, 3–14 mm wide, almost always glabrous, with the epidermis cells usually tuberculate; sides straight or slightly convex; outer margin rounded, usually entire, rarely crenulate. Pedicel slender, flexible, gently curved, usually erect, but also horizontally spreading or even growing towards the ground and thus burying the sporocarp into the soil, (6–)8–15 mm long, appressed pilose at first, later quite glabrous. Sporocarps solitary, rarely in groups, brown, broadly elliptic (rarely subcircular) in lateral view, elliptic or obtusely rhombic in dorso-ventral cross-section, 3.8–5.5 mm long, 3–4.5 mm wide, up to 3.8 mm thick, distinctly bordered at first, inconspicuously bordered when fully mature, appressed pilose at first, later gradually glabrescent; lateral veins (as seen on the interior surface) mostly anastomosing; lateral ribs 6–8, hardly visible in mature sporocarps; raphe very distinct, broad, collar-like, attached to the sporocarp; inferior tooth very inconspicuous or sometimes developed as a prominent obtuse hump; superior tooth always distinct, short, broadly conical, subacute, or acute, rarely obtuse. Sori 8–10(–12). Fig. 1.1 (page 4).

* A. Braun merely says “collected by Schweinfurth in Djur in July 1869” without citing numbers but Schweinfurth collected the species under 3 numbers so Verdcourt takes Launert’s ‘holo.’ as a lectotypification.

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MARSILEACEAE

MARSILEA

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7a

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7b

8 3

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10

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FIG. 1. — MARSILEA, sporocarps of species: 1, M. gibba; 2, M. subterranea; 3, M. nubica var. gymnocarpa; 4, M. distorta; 5, M. coromandelina; 6, M. botryocarpa; 7a, M. minuta var. minuta; 7b, M. minuta var incurva; 8, M. fadeniana; 9, M. farinosa; 10, M. macrocarpa; 11, M. megalomanica. 1 from Schweinfurth 2464; 2 from Perrotet 2464; 3 from Perrotet 182; 4 from Leprieur s.n.; 5 from Bremekamp & Schweikerdt 193; 6 from Drummond & Hemsley 4211; 7a from Robson 947, 7b from Perrotet s.n.; 8 from type; 9 from Dinter 7688; 10 from Kinges 2200; 11 from type. 1–7, 9–10, drawn by D. Erasmus; 8, 11 drawn by V. Goaman.

MARSILEA

MARSILEACEAE

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UGANDA. Busoga District: near Jinja, Mwiri, Turtle Pool, 30 Mar. 1952, Cott & Lowe in EAH 11519! KENYA. Laikipia District: Kirumun, July 1975, Powys 67!; Nairobi District: Nairobi, Langata, corner of Lamwia and Milima roads, 7 June 1974, Faden et al. 74/827!; Masai District: Aitong, 13 June 1961, Glover et al. 1819! TANZANIA. Musoma District: Serengeti, Seronera, 22 Mar. 1961, Greenway 9878!; Pare District: N Pare Mts, km 284 Lembeni to Kahe, June 1915, Peter 11410!; Iringa District: Mdonya Sand R. springs, 13 May 1970, Greenway & Kanuri 14513! DISTR. U 3; K 3–6; T 1, 3, 4, 5?, 7; Mali, Congo (Brazzaville), Congo (Kinshasa), Rwanda, Sudan, N Zambia HAB. Seasonal pools, muddy ditches, rock pools, either in water or on dried-out mud; 800–1800 m SYN. [M. uncinata sensu Peter, F.D.-O.A. 1: 92 (1929), non A. Braun]

2. M. subterranea A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 433 (1864); Hieron. in V.E. 2: 65 (1908); Tardieu & Alston in Mém. I.F.A.N. 50: 16, t. 2, fig. 5, 6 (1957); Alston, Ferns W.T.A.: 25 (1959); Launert in Senck. Biol. 49: 281, fig. 7 (1968) & in Garcia de Orta, Sér. Bot. 6: 123, t.1 fig. 5 (1985). Type: Senegal, Perrottet 996 (B!, holo., BM!, K!, iso.) Loosely to densely caespitose plant; rhizome slender, glabrous (even at the nodes) or rarely scattered pilose; internodes 0.5–5 cm long. Stipes slender, erect, 2–10(–18) cm long, striate. Leaflets yellowish-green or bright green, broadly obtriangular to narrowly obtriangular, 8–20 mm long, 4–15 mm wide, somewhat pilose when young, later glabrous or rarely very scattered pilose; sides concave to convex; outer margin rounded, usually entire, sometimes slightly irregularly crenulate or dentate. Pedicel growing horizontally or more often vertically into the ground, rather stout, 2–5 mm long, usually glabrous, rarely sparsely pilose. Sporocarps solitary at the nodes, rarely in groups, brown, broadly oblique-elliptic in lateral view, elliptic-rhombic (almost lemon-shaped) in dorso-ventral cross-section, 3–3.5 mm long, 2.2–2.8 mm wide, up to 2.5 mm thick, slightly bordered when fully mature (much more so when young), appressed pilose at first soon becoming glabrous; lateral ribs 6–8, distinct at first, almost disappearing in fully mature sporocarps; lateral veins (as seen on the interior surface) clearly anastomosing; raphe distinct, covering 4/5 to all of the sporocarp base; teeth present but not very prominent, the inferior a rather shallow hump, the superior broadly conical, obtuse to subacute. Sori 6–8(–10). Fig. 1.2 (page 4). TANZANIA. Musoma District: Serengeti, Seronera to Banagi, 4 Apr. 1961, Greenway 9978!; Dodoma District: Dodoma–Arusha road km 56, 31 Aug. 1964, Richards 19109! & about 39 km E of Itigi Station, 23 Apr. 1964, Greenway & Polhill 11706! DISTR. T 1, 5; Senegal HAB. On black cracking clay in a drying up waterhole, seasonal pools and edges of small streams; 900–1250 m

3. M. nubica A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 432 (1864); Hieron. in V.E. 2: 67 (1908); F.D.-O.A. 1: 92 (1929); Tardieu & Alston in Mém I.F.A.N. 50: 14, t. 1, fig. 5, 6 (1957); Alston, Ferns W.T.A.: 25 (1959); Launert in Senck. Biol. 49: 281, fig. 10–13 (1968) & in Prod. Fl. SW.-Afr. 11: 4 (1969) & in C.F.A., Pterid.: 57, t. 7, fig. g (1977); Schelpe & Diniz, Fl. Moçamb., Pterid.: 58, t. IV fig. c (1979); W. Jacobsen, Ferns S. Afr.: 475. t. 354 (1983); Schelpe & Anthony, F.S.A., Pterid.: 57, fig. 16/1 (1986); J.E. Burrows, S. Afr. Ferns: 67, fig. 15/62, 62a (1990); Schippers in Fern Gaz.: 212 (1993). Type: Sudan, Kordofan, Arasch-Cool, Kotschy 126 (B!, holo., BM!, FR!, L!, M!, PRC!, iso.) Rhizome very slender, repeatedly branched, forming a widespread system, bearing fronds 0.5–2 cm apart. Stipes rather weak, slender, 2–18 cm long, glabrous. Leaflets rather variable, from broadly obtriangular to very narrowly obtriangular, (1–)3.5–10 mm long, 1–9 mm wide, with the outer edge rounded, always entire, glabrous or very rarely

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MARSILEA

scattered pilose; floating forms with short or long brown suberose streaks between the veins of the lower surface. Pedicel straight or curved, rather short, free, 0.5–2.5(–3) mm long; the angle between pedicel and longitudinal axis of the sporocarp varying from 90° to 30°. Sporocarps solitary or sometimes crowded at the very base of the stipe, appearing almost sessile, black and usually shiny, very variable in shape and size, from semi-circular, rounded, square or rectangular to broadly or narrowly triangular in lateral view (most commonly as seen in Fig. 1.3), elliptic to oblong-elliptic in a dorsoventral cross-section, 2–3.5 mm long, 1.5–2.5(–3) mm wide, up to 2 mm thick, densely or moderately pilose at first, later glabrous, often punctate (the tiny dots representing the scars left by hairs), the outer black layer of the epidermis becoming detached and peeling off in irregular papery pieces; lateral ribs not apparent; veins (as seen on the interior surface) not anastomosing; raphe distinct, fully developed along the entire base of the sporocarp; inferior tooth not developed, superior tooth just indicated as a tiny dot on a broadly cone-shaped base, only to be seen after the outer layer of the epidermis becomes detached. Sori 4–5. var. nubica; Launert in Garcia de Orta, Sér. Bot. 6: 123, t. 1, fig. 6 (1985) Sporocarps with long axis usually at a right angle to the pedicel or nearly so, mat to glossy black, broadly rectangular to almost square or rarely broadly elliptic in lateral view, rectangular or biscoctiform in dorso-ventral cross-section, densely and coarsely dotted, the dots representing the scars left by hairs; outer layer of epidermis usually becoming detached. KENYA. Teita District: Tsavo National Park (East), Buchuma Waterhole, 28 Dec. 1971, Faden et al. 71/967! & Aruba–Buchuma road 1.7 km towards Aruba from sign post 153, 22 Jan. 1972, R.B. & A.J. Faden 72/75! & Dika Plains, Dika Harea road, 1.5 km from sign post 149 towards Dika Plains, 23 Jan. 1972, R.B. & A.J. Faden 72/108! TANZANIA. Pare District: Mkomazi to Mkombara, Peter 10804! DISTR. K 7; T 3; Mauritania, Senegal, Central African Republic, Sudan, Namibia, Angola and Madagascar HAB. Shallow ponds, seasonal rain pools or on wet sandy soil, often abundant and forming large colonies; 400–500 m var. gymnocarpa (A. Braun) Launert in Garcia de Orta, Sér. Bot. 6: 124, t. 2, fig. 7 (1985); J.E. Burrows, S. Afr. Ferns: 67, fig. 15/62b, c, d (1990). Type: Senegal, Leprieur in Perrottet 182 (P!, holo., BM!, L!, iso.) Sporocarps with long axis at a downward pointing angle to the pedicel, dark red-brown to black, always very glossy, broadly or narrowly triangular to rarely semicircular in lateral view, elliptic to oblong-elliptic in dorso-ventral cross-section, finely and more diffusely dotted when mature and with outer layer of epidermis becoming easily detached. Fig. 1.3 (page 4). DISTR. T? (see Note); West Africa from Mauritania and Senegal to Sudan and Namibia, Madagascar HAB. Unclear; elsewhere in shallow ponds and on wet sandy soils SYN. M. gymnocarpa A. Braun in Monatsb. K. Preuss Akad. Wiss. Berlin 1863: 432 (1864); Tardieu & Alston in Mém. I.F.A.N. 50: 14 , t. 1, fig. 7, 8 (1957); Alston, Ferns W.T.A.: 25 (1959) [M. pygmaea sensu Hieron. in V.E. 2: 67 (1908), non Brongn.] NOTE. This is recorded for Tanzania by Launert but no specimens are cited; Launert’s original notes have been lost. It could occur and has been retained here (eds).

4. M. distorta A.Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 433 (1864); Alston, Ferns W.T.A.: 25 (1959); Launert in Senck. Biol. 49: 284, fig. 14–16 (1968); Schelpe & Diniz, Fl. Moçamb., Pterid.: 61, t. V, fig. a (1979); W. Jacobsen, Ferns S. Afr.: 476 (1983); Launert in Garcia de Orta, Sér. Bot. 6: 125, t. 2, fig. 8 (1985); Schelpe & N.C. Anthony, F.S.A. Pterid.: 59 (1986); J.E. Burrows, S. Afr. Ferns: 68, fig. 15, 64, 64 a, b (1990); Schippers in Fern Gaz. 14: 211 (1993). Type: Senegal, near Dagana-Oallo, Leprieur s.n. (B!, holo., FR!, L!, P!, iso.) ˆ

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MARSILEACEAE

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Densely caespitose plant, often forming large colonies; rhizome slender, wiry, repeatedly branched, glabrous except for the usually villous nodes; internodes 0.5–5 cm long. Stipes rather slender, wiry, erect, straight or curved, 1–10(–15) cm long, usually quite glabrous, rarely scattered pilose. Leaflets grass-green to olivegreen, obtriangular to narrowly obtriangular, usually slightly asymmetrical, 6–11(–15) mm long, 4–8(–11) mm wide, with the sides curved inwards or straight, outer edge rounded to almost straight, irregularly crenate or dentate, rarely entire, with long linear pellucid streaks between the veins (the edges of these streaks, which are formed by sclerenchymatic tissue, appear prominent as parallel ridges on the lower surface of the leaflets), scattered pilose to almost glabrous. Pedicels free at the base, spreading or deflexed, flexuous, often encircling the entire sporocarp, usually growing downwards and thus burying the sporocarp in the soil, terete, rather slender, 4–12(–14) mm long. Sporocarps usually crowded at the very base of the stipes, brown, broadly elliptic to oblong-elliptic in lateral view, elliptic in the dorsoventral cross-section, 3.5–4.5 mm long, 2.7–3.3 mm wide, 1.8–2.5 mm thick, not bordered, always densely brownish tomentose; lateral ribs 6–12, visible to a varying degree, rarely invisible; veins (as seen on the interior surface) not anastomosing; raphe distinct, prominent, but very short, only attached to 1/5 – 1/3 the length of the base of the sporocarp; inferior tooth represented as the somewhat recurved apex of the raphe, always distinct, prominent, obtuse; superior tooth obsolete, just indicated by a circular area above the inferior one, very rarely slightly raised. Sori (8–)10–14. Fig. 1.4 (page 4) & Fig. 2.1 (page 8). TANZANIA. Moshi District: Kware [Gware], Aug. 1928, Haarer 1468! DISTR. T 2; Mauritania, Mali, Senegal, Liberia, Zambia, Mozambique HAB. No East Africa data; elsewhere in seasonally inundated areas, swamps, on lake shores; 1050 m SYN. [M. subterranea sensu Tardieu & Alston in Mém. I.F.A.N. 50: 16, t. 2, fig. 5, 6 (1957), non A. Braun] NOTE. There is not much ecological information available. It seems that the plant only appears in these localities after the water has subsided. The fronds seem to be adapted to terrestrial conditions. I have not seen any specimen indicative of aquatic conditions. M. distorta is distinguished not only by its peculiar features of both the sporocarp and the pedicel attachment but also by its frond. It is one of the few species in the genus which can positively be determined by vegetative characters. These are the shape of the narrowly cuneate-deltate leaflets in connection with the density of pellucid streaks in them. Although clearly defined and typified by A. Braun, M. distorta has often been confused with M. subterranea (e.g. Tardieu & Alston 1957). Both species have in common the tendency for their sporocarps to be buried in the soil but they are otherwise quite different as is shown in the key. The positive geotropic mode of growth is peculiar to some other species which are not at all related to M. distorta. A specimen Michelmore 435 said to be from ‘Tanganyika’ is in fact from NW Zambia but the species will doubtless be found in T 4.

5. M. coromandelina Willd., Sp. Pl. ed. 4, 5: 539 (1810); Launert in Senck. Biol. 49: 285, fig. 17–23 (1968) (as ‘coromandeliana’) & in Prodr. Fl. S.W. Afr. 11: 3 (1969) (as ‘coromandeliana’) & in F.A.C., Marsileaeae: 2, t. 1 fig. c–e (1975) & in C.F.A., Pterid.: 54, t. 7, fig. e (1977); Schelpe & Diniz, Fl. Moçamb. Pterid.: 62, t. V, fig. c (1979); Pic. Serm. in B.J.B.B. 53: 241 (1983); W. Jacobsen, Ferns S. Afr.: 477, t. 355 (1983); Launert in Garcia de Orta, Sér. Bot. 6: 125, t. 2, fig. 9 (1985); Schelpe & N.C. Anthony, F.S.A., Pterid.: 59 (1986); J.E. Burrows, S. Afr. Ferns: 68, fig. 15/64, 64 a, b (1990); Schippers in Fern Gaz.: 211 (1993). Type: India, Coromandel coast, Tranquebar, Klein in Herb. Willdenow 20253 (B-W!, holo.) Rather delicate, very loosely caespitose plant; rhizome slender, very thin, often thread-like, long creeping, repeatedly branched, glabrous or villous at the nodes. Stipes very slender, filiform, flexible, 1–7(–12) cm long, usually glabrous. Leaflets narrowly cuneate-obtriangular or narrowly obtriangular to obtriangular, rather small, (1.5–)2–8(–19) mm long, 1.2–6(–8) mm wide, usually quite glabrous, rarely

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MARSILEACEAE

MARSILEA

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3 FIG. 2. — 1, MARSILEA DISTORTA, habit; 2, M. BOTRYOCARPA, habit; 3, M. MINUTA var. MINUTA, base of stipe with sporocarps; 4, M. FADENIANA, base of stipe with sporocarps; 5, M. MEGALOMANICA, habit. 1 from Leprieur s.n.; 2 from Drummond & Hemsley 4211; 3 from Robson 947; 4 from type; 5 from type. 1–3 drawn by D. Erasmus, 4–5 drawn by V. Goaman.

MARSILEA

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sparsely pilose, with pellucid streaks of various lengths between the nerves; sides usually straight; outer margins round, usually entire, occasionally crenulate or bilobate. Pedicels free from each other, rather slender, wiry, often filiform, flexible, straight or more often gently curved upwards, 5–15(–25) mm long, usually glabrous. Sporocarps solitary, very rarely somewhat crowded, subcircular to broadly elliptic in outline, lemon-shaped in dorso-ventral cross-section, 2–3.8(–4) mm long, 1.5–2.5(–2.7) mm wide, up to 1.75 mm thick, always distinctly bordered all round, with the lateral walls conspicuously bulging when fully mature, appressed pilose when young, soon becoming glabrous; lateral ribs almost always visible (more prominent in young specimens); lateral veins (as seen on the interior surface) not anastomosing; raphe distinct, often short, covering 1/2 – 2/3 the length of the sporocarp base, usually broadened and often forming a ridged collar-like structure; teeth both prominent, the sinus between them somewhat elongate and shallow, the inferior obtuse, usually downwardly pointed, the superior broadly conical, obtuse to subacute or sometimes acute, straight or pointed downwards. Sori (6–)8–12. Fig. 1.5 (page 4). KENYA. Teita District: Tsavo National Park (East), Aruba to Sala Gate Road, 9 km towards Aruba from signpost 106, 7 Jan. 1972, R.B. & A.J. Faden 72/26! & Aruba to Ndara road, 1.2 km W of signpost 153, 14 Jan. 1972 Faden et al. 72/76! & Aruba–Buchuma road, 1.7 km from signpost 153 towards Aruba, 22 Jan. 1972, R.B. & A.J. Faden 72/83! TANZANIA. Moshi District: Kware [Gwari], Aug. 1928, Haarer 1467!; Pare District: Mkomazi to Mkumbara, June 1915, Peter 10805!; Usaramo District: 16 km N of Dar es Salaam, Kawe Rifle range, 7 July 1971, Batty 1322! DISTR. K 7; T 2, 3, 6; Mauritania, Senegal, Burundi, Angola, Namibia, South Africa; also in Madagascar & India HAB. Lake shores, seasonal pools and waterholes, often forming very large colonies on moist ground in seasonally swampy areas; 0–1050 m SYN. M. pygmaea Brongn. in Bory, Dict. Class. Hist. Nat. 10: 199 (1826). Type: Senegal, Leprieur s.n. (P!, holo.) M. muscoides A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 422 (1864); Hieron. in V.E. 2: 66, fig. 64 (1908); Alston, Ferns W.T.A.: 25 (1959). Type: Senegal, Leprieur 182 & Perrottet s.n. (P!, syn.) M. trichopoda A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 422 (1864); Hieron. in V.E. 2: 66, fig. 63 (1908); F.D.-O.A. 1: 91 (1929) (as ‘trichopus’); Tardieu, Fl. Madagascar 10: 3 (1953); Tardieu & Alston in Mém. I.F.A.N. 50 (1957); Alston, Ferns W.T.A.: 25 (1959). Type: Senegal, Leprieur s.n. (P!, holo.) M. microphylla C. Chr. in Dansk Bot. Arkiv 7: 180, t. 73, fig. 8, 9 (1932). Type: Madagascar, Ambongo, near Soalala, Perrier de la Bâthie 7188 pro parte (BM!, holo.) NOTE. The great variability of this species has vexed many students of the past. A. Braun in his first publication on the classification of Marsilea (1864: 416) indicated that coromandelina and trichopoda were mere “Formen” of one species. Despite this, in his more comprehensive study (1871) he maintains the two taxa as species but states in his notes on trichopoda that it is an intermediate between coromandelina and muscoides. J.G. Baker (Handb. Fern-Allies, 1887), who did not provide a key to the individual species, followed A. Braun in maintaining them as separate species. Later workers studied the genus only on a regional basis which accounts for the increase in the number of synonyms. C. Christensen (1932) defines M. microphylla as follows “its nearest relative is perhaps M. muscoides Leprieur from Senegambia, a species unknown to me …”. The myth that everything occurring in Madagascar must be endemic may also have been a contributory factor towards his decision to describe a new species. In fact M. microphylla is virtually identical with the specimen on which M. muscoides is based. Bremekamp’s M. trichocarpa was founded on a very immature specimen. In more recent material from South Africa (e.g. Codd 4096) the sporocarps do not differ at all from those of tropical African or even Indian material. I have not yet seen any aquatic forms of coromandelina from Africa. All the specimens from southern Angola, Namibia and South Africa are terrestrial forms with very narrowly cuneate leaflets. The interstitial pellucid streaks in the leaflets of M. coromandelina are usually shorter, less prominent, and fewer than in M. distorta. They are much more developed in terrestrial forms than in aquatic ones, and in the latter case one often has to examine the leaflets in strong transmitted light in order to recognise them. The only species with which M. coromandelina can perhaps be confused is M. gibba, which occasionally has slightly bordered sporocarps. On herbarium labels as well as in

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literature, e.g. Baker (1887), one finds the specific epithet spelled “coromandelica”, based on Burman’s Flora Indica (1767). Since Burman not only published his name in synonymy (under quadrifolia Linnaeus) but was also not sure of its taxonomic status, his name is invalid. Linnaeus (Mant. Pl. Alt.: 308 (1771)) mentions the name as minuta ß coromandelina (as ‘cormandeliana’) without giving it the rank of a variety. He just refers to Burman’s name. Thus the first valid publication was effected by Willdenow, and the type is certainly the specimen in Willdenow’s herbarium.

6. M. botryocarpa Ballard in Hook. Ic. Pl. 36, t. 3600 (1962); Launert in Senck. Biol. 49: 290, fig. 29–31, 68 (1968) & in Senck. Biol. 52: 449, fig. 1 (1971) & in Garcia de Orta, Sér. Bot. 6: 125, t. 3, fig. 12 (1985). Type: Kenya, Kwale District, between Samburu and Mackinnon Road, Taru, Drummond & Hemsley 4211 (K!, holo.) Plant with a long creeping rhizome. Stipes very slender, 4–24 cm long, scattered pilose. Leaflets obtriangular, 0.7–3 cm long, 0.5–2.7 cm wide, glabrous on the upper, scattered pilose on the lower surface, sides straight or slightly concave, the outer margin rounded, deeply irregular crenate. Pedicels equalling or twice the height of the sporocarp, connate, forming branches of a dichotomously branched common peduncle-like structure. Sporocarps in up to 3 loose clusters of 14–17, borne midway along the stipe, dark brown to blackish when mature, shallowly saddle-shaped to bean-shaped, 5–5.5 mm long, 3–3.5 mm wide, 1.5–2 mm thick, appressed pilose when young, later glabrous, not distinctly bordered but with the centre part laterally somewhat bulging; lateral ribs not visible in mature sporocarps; lateral veins (as seen on the interior surface) not anastomosing; raphe present, covering 1/2 – 2/3 the length of the sporocarp base; inferior tooth indicated by a very shallow hump; superior tooth prominent, short, subacute. Sori 6–8. Fig. 1.6 (page 4) & Fig. 2.2 (page 8). KENYA. Teita District: Tsavo National Park (East), Dika Plains–Dida Harea road, 23 Jan. 1972, R.B. & A.J. Faden 72/101!, 72/102!; Kwale District: between Samburu and MacKinnon Road, Taru, 8 Sep. 1953, Drummond & Hemsley 4211!; Tana River District: Tana River National Primate Reserve, 13 Mar. 1990, Luke et al. T.P.R. 284! DISTR. K 7; not known elsewhere HAB. Seasonal pools and waterholes; 30–600 m NOTE. Reservations that this might not be distinct from M. ephippiocarpa Alston were completely dispersed on the discovery of a second specimen in Tsavo National Park by Evans and Maikweki in 1971, since when several more localities have been discovered.

7. M. minuta L., Mant. Pl.: 308 (1771); Launert in Senckenb. Biol. 49: 291, figs. 32–34, 69 (1968) & in F.Z., Pterid.: 60, t. 17, fig. b (1970); Schelpe, Expl. Hydrobiol. Bassin L. Bangweolo & Luapula 8 (3) Pterid.: 36 (1973); Launert, F.A.C. Marsiliaceae: 3, t. 1 fig. a, b (1975) & in C.F.A. Pterid.: 55, t. 7, fig. f (1977); Schelpe & Diniz, Fl. Moçamb. Pterid.: 55, t. IV fig. d (1979); Pic. Serm. in B.J.B.B. 53: 241 (1983); W. Jacobsen, Ferns S. Afr.: 479, t. 357 (1983); Schelpe & N.C. Anthony, F.S.A. Pterid.: 60 (1986); Schippers in Fern Gaz. 14: 212 (1993); Faden in U.K.W.F. ed. 2: 37 (1994). Type: India, Linn. Herb. 1254. 6 (LINN!, lecto., chosen by Launert, 1968) An extremely variable plant, aquatic, subterrestrial or more rarely terrestrial, usually very loosely caespitose; rhizome slender to fairly stout, long creeping, repeatedly branched, glabrous or villous at the nodes (especially in terrestrial forms); internodes 0.5–20 cm long. Stipes of floating leaves slender, up to 25 cm long, otherwise 2–8(–15) cm long, usually glabrous. Leaflets obtriangular to broadly obtriangular, 0.4–2.5(–3) cm long, 0.3–2.2(–2.8) cm wide, usually quite glabrous but sparsely pilose in terrestrial forms, with brownish suberose streaks between the veins of the lower surface of floating leaves; sides varying from straight to convex, rarely concave; outer margin rounded, entire in floating leaves; entire, sinuate or crenulate in aerial or subaerial ones. Pedicel erect or gently curved upwards, free or united to

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11

some extent with 2 or 3 (rarely 4) others (see Fig. 2.3), usually inserted at the very base of the stipe but not infrequently arising separately (or in groups of 2) one above the other above the base of the stipe, fairly stout, terete, (2–)3–7 mm long, appressed pilose at first, later becoming glabrous. Sporocarps usually crowded, more rarely in groups of 2 or 3, very rarely solitary (see also description of pedicel), extremely variable in size, dark brown to almost black at maturity, broadly oblong, broadly elliptic or very rarely subcircular in lateral view, distally always rounded, elliptic in dorso-ventral cross-section, (2.8–)3–4(–6) mm long, 2.4–3(–4.8) mm wide, 0.8–1.4(–2) mm thick, often bordered to a varying degree (mainly in Indian specimens), without dorsal or frontal furrow or suture, densely appressed pilose when young, usually quite glabrous when mature; lateral ribs visible (mainly in Indian specimens) or invisible; lateral veins (as seen on the interior surface) not anastomosing; raphe distinct, attached to 2/3 or the entire length of the sporocarp base; teeth usually prominent, the inferior shorter than or occasionally as long as or sometimes even longer than the superior, obtuse to subacute, erect or rarely slightly recurved, the superior narrowly conical, acute, rarely subacute or obtuse, erect or recurved. Sori 8–12. var. minuta; Launert in Garcia de Orta Sér. Bot. 6: 125, t. 3, fig. 13 (1985); J.E. Burrows, S. Afr. Ferns: 72, fig. 16/66, 66a, b (1990) Sporocarps dark brown to black when mature, broadly oblong to oblong-elliptic or rarely subcircular in lateral view, elliptic in dorso-ventral cross-section, 2.8–4 mm long, 2.4–3 mm wide, usually smooth except for hair scars, rarely wrinkled (when dry), its long axis usually at a right angle to the pedicel which is usually longer than the sporocarp; superior tooth always prominent, narrowly conical, acute or very rarely subacute; inferior tooth subacute or obtuse, erect or rarely slightly recurved, sometimes as long as the superior. Fig. 1.7a (page 4) & Fig. 2.3 (page 8). UGANDA. Acholi District: Adilang, 19 Nov. 1945, A.S. Thomas 4415!; Masaka District: 17–18 km SE of Ntusi, 19 Oct. 1969, Lye & Rwaburindore 4504!; Mengo District: 74 km Masindi road, 16 Sep. 1960, Lind 2722a! KENYA. Fort Hall/Kiambu District: Thika, Perkins in EA 11502!; Kilifi District: Malindi, May 1960, Rawlins 944!; Lamu District: Mkunumbi, Feb. 1957, Rawlins 362! TANZANIA. Mbulu District: Bubu R., Gidas Village, 18 Mar. 1974, Richards & Arasululu 28967!; Uzaramo District: Dar es Salaam, Observation Hill road, 16 Dec. 1938, Vaughan 2546!; Rungwe District: Mwaya, 22 Aug. 1933, Greenway 3591! DISTR. U 1, 2?, 4; K 4, 7; T 2–4, 5?, 6, 7; Algeria, Mali, Senegal, Ghana, Dahomey, Nigeria, Central African Republic, Congo (Kinshasa), Burundi, Sudan, Angola; Madagascar and Comoro Is.; possibly in Somalia HAB. Shallow pools, edges of rivers, rocks underneath waterfalls, water holes, seasonally dried up river beds, seasonally swamped grassland depressions, rice fields; often forming large and dense colonies; 0–1950 m SYN. M. crenulata Desv., Prodr.: 179 (1827); Hieron. in V.E. 2: 65 (1908) (as Marsilia); Tardieu & Alston in Mém. I.F.A.N. 50: 13, t. 1, fig. 3, 4 (1957); Tardieu, Fl. Cameroun 3: 57 (1964). Type: Réunion, Commerson s.n. (P!, holo.) M. diffusa A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 419 (1864); Hieron. in P.O.A. C: 90 (1895) & V.E. 2: 65 (1908), F.D.-O.A. 1: 91 (1929); Tardieu, Fl. Madagascar 10: 2 (1952); Alston, Ferns W.T.A.: 24 (1959). Type: Senegal, Lelièvre s.n. (B!, holo., P!, iso.) M. tenax Peter in Abh. Ges. Wiss. Göttingen, Math.-Phys. Kl., N.F. 13: 38 (1928) & F.D.-O.A. 1: 91 & Descriptiones: 2 (1929). Type: Tanzania, N Pare Mts, Njata Hill to Lake Jipe, Peter 14114* (B, holo.!, BM!, iso., K!, iso.) NOTE. M. minuta is the widest distributed species of the genus and by far the most variable. The long list of synonyms (see Launert, op. cit.) already suggests that this species has vexed generations of taxonomists. If one studies a large number of specimens one soon realises that the main differences are rather of a quantitative than of a qualitative nature. Throughout the

* Although Peter cites two specimens on p. 11 in the actual description he gives only 14114 as the type.

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vast area of distribution of this species the basic shape as well as the essential characters of the sporocarp (pedicel attachment, teeth, and number of sporocarps per stipe) remain very constant. The differences mainly lie in the number of sporocarps and their size. Anyone who has undertaken a taxonomic study of aquatic or semi-aquatic plants will agree that it would be a waste of time to discuss the scientific value of the numerous infraspecific taxa that have been described of tropical plants of this nature in the past. Most of these taxa simply reflect the phenotypic plasticity which is typical for this widely disseminated species. There are some fine specimens from tropical Africa from which, if closely divided, one could produce at least three herbarium specimens each representing a different variety. The growth of the plant is often so dense and vigorous that large quantities of it are used as a substitute for Osmunda fibre for growing orchids. var. incurva (A. Braun) Launert in Garcia de Orta, Sér. Bot. 6: 126, t. 3, fig. 14a, b, c (1985). Type: Senegal, Perrottet s.n. (B!, holo.) Sporocarps usually black when mature (rarely dark brown), broadly elliptic, rectangularelliptic to rarely subcircular in lateral view, narrowly elliptic to rectangular-elliptic or rarely biscoctiform in dorso-ventral cross-section, (4.5–)5–6(–6.2) mm long, (3–)3.5–4(–5) mm high, with the dried surface coarsely wrinkled or rarely smooth (except for hair scars), its long axis usually at an angle exceeding 90° with the pedicel, which is usually shorter than the sporocarp is long. Fig. 1.7b (page 4). KENYA. Tana River District: Tana R. National Primate Reserve, 1 km S of main gate, 19 Mar. 1990, Luke et al. TPR672!; W side of Garsen to Malindi road 3–4 km S of junction with Hola road, 25 Oct. 1978, Schippers in EA 16298! TANZANIA. Kilosa District: Kikarawaza, 20 June 1973, Greenway & Kanuri 15181! DISTR. K 7; T 6; Senegal to Ghana HAB. Drainage channels in open woodland, seasonal waterhole on black cotton soil; 50–550 m SYN. M. diffusa A.Braun var. incurva A. Braun in Monatsb. K. Preuss. Akad. Wiss. Berlin 1863: 419 (1864) M. crenulata Desv. var. incurva (A. Braun) A. Braun in Kuhn, Filices Afr.: 198 (1868) M. senegalensis Bak., Fern Allies: 141 (1887); Alston, Ferns W.T.A.: 25 (1959). Type as above

8. M. fadeniana Launert in Garcia de Orta Sér. Bot. 6: 126, t. 1, fig. 2 (1985). Type: Kenya, Kwale District, near Samburu, Evans & Maikweki 55 (BM!, holo., BOL!, EA!, FR!, GE!, K!, US!, iso.) Plant caespitose; rhizome creeping, branched, at first hairy at the nodes but soon glabrescent; internodes 0.3–1.2(–5) cm long, 0.5–1.5 mm thick. Stipes 3–7 mm long, sparsely pilose or glabrous, smooth, often narrowly striate. Leaflets triangular to triangular obovate, 0.7–2 cm long, 0.5–1.7 cm wide, cuneate at the base, entire to erose-crenate at margin, sparsely greyish pilose when young, often glabrous when adult. Sporocarps borne above surface, in groups of 3–6, not deflexed towards petiole, sessile or very shortly pedicellate, subrectangular or obliquely semi-elliptic in outline, 4.5–6 mm long, 3.2–3.8 mm wide, moderately compressed, adpressed pilose; lateral veins distinct up to ventral margin; superior tooth shortly conical, acute or subacute; inferior tooth indistinct, obtuse. Sori 7–9. Fig. 1.8 (page 4) & Fig. 2.4 (page 8). KENYA. Kwale District: Mombasa–Nairobi road, 2.8 km from Samburu towards Mackinnon road, 29 May 1971, Evans & Maikweki 55! & 5.7 km from Samburu, 1974, R.B. & A.J. Faden 74/1278! DISTR. K 7; not known elsewhere HAB. Dry streambed, seasonal waterhole in dry bushland zone; ± 300 m SYN. M. glomerata Launert in Senck. Biol. 52: 449, figs. 2–3 (1971), non Presl (1845) NOTE. The most remarkable feature of this species, in which it differs from all other species of the genus, is the complete absence of a marked pedicel. The base of the sporocarp is situated on a short tapering blackish conical base; 3–6 sporocarps, with their bases partly united, form

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13

dense clusters. These clusters are inserted on the rhizome at the base of the stipe with the individual sporocarps in a vertical or semi-vertical position. The arrangement of sporocarps in clusters is known from two other species namely M. botryocarpa and M. ephippiocarpa Alston. In both these species the sporocarps are clearly pedicellate and borne on a common peduncle-like structure. Whereas the loosely arranged cluster is borne about midway along the stipe in M. botryocarpa, it is situated at its base in M. ephippiocarpa. The sporocarps of M. ephippiocarpa differ from those of M. botryocarpa in being saddle-shaped and about as long as wide. The affinities of the new species lie, therefore, with M. botryocarpa rather than M. ephippiocarpa. Besides having no distinct pedicel the sporocarp of M. fadeniana differs from that of M. botryocarpa by its more pronounced superior tooth and by being dark brown to almost black in colour when mature. Material from the type has been grown at the Chelsea Physic Garden (MO!).

9. M. farinosa Launert in Senck. Biol. 49: 298, figs. 41–46, 70–71 (1968) & in Prod. Fl. SW. Afr. 11: 4 (1969) & F.Z. Pterid.: 65, t. 17, fig. c (1970) & in C.F.A., Pterid.: 55, t. 7, fig. a (1977); Schelpe & Diniz, Fl. Moçamb., Pterid.: 60, t. IV, fig. a (1979); W. Jacobsen, Ferns S. Afr.: 481, t. 360 (1983); Launert in Garcia de Orta, Sér. Bot. 6: 127, t. 4, fig. 17 (1985); Schelpe & N.C. Anthony, F.S.A., Pterid.: 61 (1986); J.E. Burrows, S. Afr. Ferns: 73 (1990); Schippers in Fern Gaz. 14: 212 (1993); Faden in U.K.W.F. ed. 2: 37 (1994). Type: Namibia, Grootfontein, Schönfelder in Dinter 7688 (M!, holo., BM!, BOL!, FR!, K!, PRE!, iso.) Loosely to densely caespitose plant, often forming large compact colonies, greyishgreen; rhizome rather stout, up to 2.5 mm in diameter, silvery-grey or brown, pilose or glabrous; internodes usually very short, rarely up to 5 cm. Stipes 2–15(–20) cm long, slender, usually hispid, rarely glabrous, erect. Leaflets cuneate to narrowly obtriangular, 5–16 mm long, 5–18 mm wide; sides straight, outer margin erose-lobed, sparsely pilose. Pedicels usually curved, rarely straight, relatively slender, flexible, (4–)8–15(–25) mm long, almost always hispid; the angle between the pedicel and the longitudinal axis of the sporocarp varying from 90° to almost 180°. Sporocarps usually close together, less often solitary at the base of the stipe, usually horizontal, brown, bean-shaped, 4.2–7 mm long, 3.5–4.5(–4.8) mm high, 1.5–2.3 mm thick, with a dorsal furrow which extends over the front towards the base on the ventral side, laterally slightly bulging, flat or rarely concave; lateral ribs 8–11, not conspicuous in fully mature specimens; covered with multicellular uniseriate hairs of 2 kinds, basally attached, erect ordinary cylindrical hairs and flattened hairs, which are laterally attached to the surface of the sporocarp by an usually 1-celled funicle-like stalk; raphe present, extending 1/2 – 2/3 the length of the base of the sporocarp; veins (as seen on the interior surface) not anastomosing; inferior tooth absent or very weakly developed (only indicated as a shallow hump); superior tooth present but usually rather inconspicuous, conical, obtuse or very rarely subacute. Sori 8–11. Fig. 1.9 (page 4). subsp. farinosa; J.E. Burrows, S. Afr. Ferns: 73, t. 10. 4, fig. 17/69, 69a, b (1990) Sporocarps held at ± 90° to the pedicel; pedicels arising from stipe axes only KENYA. Machakos District: SW of Lukenya Hill, 30 Mar. 1969, Greenway & Napper 13597! & Lukenya road, 15 km from Nairobi–Mombasa road, 20 Dec. 1970, Faden et al. 70/902! TANZANIA. Mbulu District: Mbulumbul, 24 June 1944, Greenway 7949!; Arusha District: Arusha to Moshi, Feb. 1914, Peter 1834b! & Arusha National Park, Maji ya Chai, 6 Jan. 1972, Greenway & Fitzgerald 14965! DISTR. K 4; T 2; Ethiopia, Angola, Mozambique (fide Burrows), Zimbabwe, Botswana, Namibia and South Africa HAB. Seasonal pools and moist banks of dry river beds, usually forming large mats; 1350–1700 m SYN. [M. fischeri sensu Peter in F.D.-O.A. 1: 92 (1929) quoad Peter 1834b, non Hieron.]

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NOTE. This is the plant which Dinter distributed widely under the manuscript name M. pubescens. It is closely related to both M. macrocarpa and M. unicornis Launert but clearly distinguished from these species by its peculiar indument which consists of a mixture of two different types of hair. The laterally attached hairs are peculiar to the genus Marsilea and besides minor variations fairly uniform throughout. M. farinosa is the only species in which ordinary uniseriate hairs could be found. In dried specimens their cells are usually collapsed and thus the hair is coiled or bent. In this state the entire plant appears greyish-farinose. In shape the sporocarps are almost identical to those of M. unicornis. In the latter species, however, the superior tooth is generally much more prominent and always acute. The assumption that M. farinosa is a segregate of M. macrocarpa is strengthened by the disjunct area of distribution. As is the case in M. macrocarpa the East African specimens are slightly larger and lozenge-shaped rather than bean-shaped; the angle between its longitudinal axis and the pedicel is usually much larger than in the South African specimens. M. farinosa seems to be semi-aquatic or terrestrial. I have not seen any specimen with floating leaves. J.E. Burrows (Bothalia 19: 169 (1989)) divided this species into two subspecies. Subsp. arrecta occurs only in NW Transvaal and S Botswana.

10. M. macrocarpa Presl in Abh. Königl. Böhm Ges. Wiss. 3: 580 (1845); Hieron. in V.E. 2: 65 (1908); Launert in Senck. Biol. 49: 300 figs. 47–52, 72–73 (1968) & in Prodr. Fl. SW.-Afr. 11: 4 (1969) & in F.Z. Pterid. 64, t. 17, fig. d (1970); Schelpe, Expl. Hydrobiol. Bassin L. Bangweolo & Luapula 8 (3) Ptérid.: 36 (1973); Launert in C.F.A., Pterid.: 56, t. 7, fig. d (1977); W. Jacobsen, Ferns S. Afr.: 483, t. 361 (1983); Launert in Garcia de Orta, Sér. Bot. 6: 127, t. 4, fig. 18 (1985); Schelpe & N.C. Anthony, F.S.A., Pterid.: 62, fig. 16/2 (1986); Burrows, S. Afr. Ferns: 74, t. 11.1, fig. 16/75 75a, b (1990); Schippers in Fern Gaz. 14: 212 (1993); Faden in U.K.W.F. ed. 2: 37 (1994). Type: South Africa, Cape Province, Drège (PRE!, holo., B!, iso.) Loosely caespitose plant; rhizome slender to stout, 0.1–1.75 mm thick, pilose or glabrous, often villous or tomentose at the nodes. Stipes variable, slender or rarely stout, (5–)10–25 (in some aquatic forms –40) cm long, usually glabrous, somewhat striate. Leaflets greyish-green to dark green, sometimes glossy on the upper surface, broadly obtriangular, more rarely narrowly obtriangular-cuneate, often broader than long, (4–)7–25(–35) mm long, (3–)5–28(–40) mm wide, sides usually concave, sometimes straight, very rarely slightly convex; outer margin round, entire or sinuate, sometimes crenulate, or crenate-dentate, rarely lobed, with long brown suberose interstitial streaks on the lower surface of floating fronds, glabrous (in aquatic forms) or pilose at first and becoming glabrous (in terrestrial forms), rarely remaining pilose. Pedicels erect or ascending, rarely growing horizontally, slender or rarely somewhat stout, free from each other, inserted at the very base of the stipe, (3.5–)7–12(–14) mm long, usually pilose, rarely glabrous; the angle between the longitudinal axis of the sporocarp and the pedicel varying from 90–180°. Sporocarps usually several, rarely solitary, brown, usually broadly elliptic or broadly ellipticoblong, but also obtusely rectangular to subcircular in lateral view, narrowly rectangular to slightly biscoctiform in dorso-ventral cross-section, very variable in size, (3.2–)4.2–6(–7) mm long, 3–4.5(–5.5) mm high, 1.5–2 mm thick, not bordered, usually with a shallow furrow along the dorsal and frontal side, which sometimes extends down to the base of the ventral side, densely appressed pilose at first, sometime villous or rarely tomentose, later becoming more sparsely pilose, rarely entirely glabrous at maturity; lateral ribs more or less distinct, often disappearing in fully mature sporocarps; lateral veins (as seen on the interior surface) not anastomosing; raphe always distinct, covering 1/3 – 1/2 (rarely 2/3) the length of the sporocarp base; inferior tooth absent or only a very shallow hump; superior tooth present, rather short, conical, obtuse or very rarely subacute to acute. Sori 8–12(–14). Fig. 1.10 (page 4). UGANDA. Teso District: 0.5 km NW of Bukedea, 9 May 1970, Lye & Katende 5359!; Busoga District: Jinja, near Busoga College, 6 July 1952, Milburn 32!

MARSILEA

MARSILEACEAE

15

KENYA. Northern Frontier District: Mathews Range, 11 Sep. 1977, Ichikawa 820!; Kiambu District: Thika, 14 Falls, 11 Sep. 1955, Napper in EA 10889!; Masai District: western slopes of Ngong Hills, 3 Sep. 1965, Kokwaro et al. 324! TANZANIA. Mbulu District: Mbulumbul, Block D1, 24 June 1944, Greenway 6949!; Moshi District: Kilimanjaro, Masama turn-off on Moshi–Arusha road, 8 Sep. 1968, Bigger 2197!; Kondoa District: Uassi, Bejolo–Gele, Aug. 1926, Peter 44300! DISTR. U 3; K 1, 3?, 4, 6; T 2, 5; Congo (Kinshasa), Angola, Zimbabwe, Namibia and South Africa HAB. Along or in streams, in dried up stream or dam beds, in seasonal pools; 800–2000 m SYN. M. dregeana A. Braun in Monatsber. K. Preuss. Akad. Wiss. Berlin 1863: 428 (1864). Type as for M. macrocarpa, nom. illegit. M. rotundata A. Braun in Kuhn, Filic. Afr.: 200 (1868); Hieron. in V.E. 2: 66 (1908). Type: Angola, Huila, Welwitsch 171 (B!, holo., BM!, iso.) M. fischeri Hieron. in P.O.A.C: 90 (1895) & in V.E. 2: 66, fig. 62 (1908); F.D.-O.A.: 92 (1929) pro parte. Type: Kenya/Tanzania, Masailand*, Fischer 677 (B!, holo., BM!, K!, iso.) NOTE. M. macrocarpa is closely related to M. apposita Launert, M. vera Launert, M. unicornis Launert, M. villifolia Alston & Schelpe and M. farinosa. Noteworthy is the area of disjunct distribution, which follows roughly the same pattern as observed in the case of M. farinosa. The plants from NE tropical Africa differ only slightly from the southern African ones by having somewhat larger sporocarps, but there are no other differences which would justify keeping fischeri as a distinct taxon. The differences between M. macrocarpa and M. rotundata, the original description of which was based on a single not fully mature specimen, as defined by A. Braun cannot be confirmed on the material which is now available for examination. Lye 5359 (Uganda, Teso District, 0.5 km NW of Bukedea) may be M. macrocarpa but is sterile.

11. M. megalomanica Launert in Senck. Biol. 51: 435, figs. 1–4 (1970) & in Garcia de Orta, Sér. Bot. 6: 127, t. 1, fig. 3 a–c (1985). Type: Kenya, Northern Frontier District, Isiolo, halfway between Dodolo Boke and Yamicha, van Swinderen Is/83 (BM!, holo., BOL!, EA!, FR!, GDOR!, US!, iso.) Plant caespitose; rhizome filiform with internodes up to 1.5 cm long; nodes densely hairy at first. Stipes graceful, slightly curved, up to 20 cm long, sulcate, sparsely pilose or almost glabrous, smooth, bearing the sporocarps towards the apex. Leaflets broadly triangular or triangular-obovate, 1.2–2.3 cm long, 0.9–1.4 cm wide, cuneate at the base, usually erose-crenate at the margin, softly grey-hairy when young, later with scattered hairs or glabrous. Pedicels slender, flexuous, 1–2 cm long, sparsely pilose or glabrescent. Sporocarps pedicellate, arranged in 2 rows on either side of the axis, subrectangular or obliquely semi-elliptic, 4–6 mm long, 3–3.8(–4) mm wide, laterally moderately compressed, covered with dense adpressed hairs; lateral veins 11–12, distinct up to the ventral margin; superior tooth shortly conical, obtuse or subacute; inferior tooth almost obsolete. Sori 7–10. Fig. 1.11 (page 4) & Fig. 2.5 (page 8). KENYA. Northern Frontier District: Isiolo, halfway between Dodolo Boke and Yamicha, van Swinderen Is/83!; Teita District: Tsavo National Park, Aruba to Buchuma road, about km 3, 22 Jan. 1972, R.B. & A.J. Faden 72/80! DISTR. K 1, 7; not known elsewhere HAB. Dry waterholes in thicket, growing in sandy soil; 300–450 m NOTE. The sporocarp is reminiscent of those of M. macrocarpa Presl and I would have had not the slightest objection to accommodating the plant in question in this species were it not for the strikingly different sporocarp arrangement. Every single sporocarp character lies well within the range of variability of M. macrocarpa. Only the pedicels are slightly more slender than is typical for this species.

* Various attempts have been made to interpret what is written on the label but it appears to be Massai with the Swahili locative suffix –ni added.

INDEX TO MARSILEACEAE Marsilea L., 1 Marsilea apposita Launert, 15 Marsilea botryocarpa Ballard, 10, 4, 8, 13 Marsilea coromandelina Willd., 7, 4, 9 Marsilea crenulata Desv., 11 var. incurva (A. Braun) A. Braun, 12 Marsilea diffusa A. Braun, 11 var. incurva A. Braun, 12 Marsilea distorta A. Braun, 6, 4, 8, 9 Marsilea dregeana A. Braun, 15 Marsilea ephippiocarpa Alston, 10, 13 Marsilea fadeniana Launert, 12, 4, 8 Marsilea farinosa Launert, 13, 4, 15 subsp. farinosa, 13 subsp. arrecta J.E. Burrows, 14 Marsilea fischeri Hieron., 13, 15 Marsilea fischeri sensu auct., 13 Marsilea gibba A. Braun, 3, 4, 9 Marsilea glomerata Launert non Presl, 12 Marsilea gymnocarpa A. Braun., 6 Marsilea macrocarpa Presl, 14, 4, 15 Marsilea megalomanica Launert, 15, 4, 8 Marsilea microphylla C. Chr., 9

Marsilea minuta L., 10 var. minuta, 11, 4, 8 var. incurva (A. Braun) Launert, 12, 4 Marsilea muscoides A. Braun, 9 Marsilea nubica A. Braun, 5 var. gymnocarpa (A. Braun) Launert, 6, 4 var. nubica, 6 Marsilea pygmaea Brongn., 6, 9 Marsilea pygmaea sensu auct., 6 Marsilea pubescens, 14 Marsilea quadrifolia L., 10 Marsilea rotundata A. Braun, 15 Marsilea senegalensis Bak., 12 Marsilea subterranea A. Braun, 5, 4, 7 Marsilea subterranea sensu auct., 7 Marsilea tenax Peter, 11 Marsilea trichocarpa Bremek., 9 Marsilea trichopoda A. Braun, 9 Marsilea uncinata A. Braun, 5 Marsilea uncinata sensu auct., 5 Marsilea unicornis Launert, 14, 15 Marsilea vera Launert, 15, Marsilea villifolia Alston & Schelpe, 15

No new names validated in this part

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