Drosera madagascariensis DC.

Rjosk, A., Neinhuis, C., Monizi, M. & Lautenschläger, T., 2022, Synopsis of the genus Drosera (Droseraceae) in Angola and the Democratic Republic of the Congo, Blumea - Biodiversity, Evolution and Biogeography of Plants 67 (1), pp. 1-14 : 10-11

8. Drosera madagascariensis DC. — Fig. 10

Drosera madagascariensis DC. (1824) 318; Diels (1906) 98; G.C.C. Gilbert (1951) 554; Keay (1954) 121; J.R. Laundon (1959) 5; Oberm. (1970) 200; J.R. Laundon (1978) 68; Troupin (1978) 307; Akoègn. et al. (2006) 539; A.S.Rob. et al. (2017) 1426. —

Type: Lambert s.n. (holo G-DC), Madagascar, 1819.

Drosera congolana Taton (1945b) 310; G.C.C. Gilbert (1951) 552. — Type: J. Bequaert 7191 (holo BR), DRC, Leopoldville, 29 Mar. 1915

Perennial, caulescent herb. Stems up to 25 cm long, rarely acau- lescent (see Note), c. 1 mm diam, only apical part of the stem self-supporting, glabrous or sparsely pilose ( Fig. 10b ). Leaves evenly spaced along the stem, alternate to spirally arranged, occasionally clustered, erect, older leaves reflexed; stipules oblong, 2–6(–8) by c. 1 mm, membranous, lacerated apically, ferrugineous; lamina obovate, elliptic or spathulate, 0.4–1.1 (–3) cm by 2–7 mm, bearing tentacles adaxially and around the margins, almost glabrous to pilose abaxially ( Fig. 10a ); petiole linear, 0.6–2(–3) cm by 0.3–1 mm, glabrous to pilose. Inflorescences cymose, with 2–15 flowers, axillary; peduncles 1–3 together; 9–55 cm long, arising laterally, ascending, basally particularly curved, glabrous, glandular or pilose; bracts linear to spathulate, 2–3 mm long, sparsely pilose, caducous; pedicels 1–10 mm long, glandular or pilose. Sepals 5, elliptic to oblonglanceolate, 4–7 by 1–2 mm, connate at the base, apex acute or obtuse, glandular and/or pilose. Petals 5, obovate, 5–12 by 3.5–6 mm, pink or purple. Stamens 5; filaments 2–5 mm long. Pollen in tetrads, tetrads c. 45 µm diam, single grains c. 30 µm diam, echinate ( Fig. 10e ), echini broadly conical, c. 2 mm long, of medium density with short clavate sculptural elements between them. Pistil: ovary subglobose to ovoid, c. 2 by 1–1.5 mm, glabrous; styles 3, c. 2 mm long, 2-partite to the base, apices clavate, white to pink. Seeds fusiform, 0.7–1 by c. 0.2 mm, brownish black, apiculate, testa reticulate.

Distribution — Widespread in tropical Africa, South Africa, Madagascar ( Fig. 10c ).

Habitat & Ecology — Perennially wet habitats (swamps, marshes, river and lake shores, perennially wet places in seasonally dry wet-savannahs).

Additional specimens (see Fig. 10d for province map). ANGOLA, Bié, Silva Porto – Andulo , km 35, S12°09' E16°45', alt. 1700 m, 15 Mar. 1973, P. Bamps et al. 4153 ( BR) ; Cusseque – TFO core site , plain, alluvial plain, fire in last dry season, S13°42' E17°6', alt. 1515 m, 29 Oct. 2011, R. Revermann 132779 ( HBG) , M. Finckh 132768 ( HBG) ; Cuando Cubango, Baixo Cubango , 179 km von Cuangar in Richtung Caiundo, sumpfiges Gelände am Rio Cubango , Moorboden , alt. 1070 m, 29 Jan. 1952, H. Hess 52/509 ( ZT) ; Menongue, Vila Serpa Pinto , pr. da confluencia do Camumbé com o Cuebe , alt. 1420 m, 12 Feb. 1960, E.J. Mendes 2482 ( COI) ; Cuito- Cuanavale, confluencia dos rios Tchiengo com o Cuito , alt. 1280 m, 3 Mar. 1960, E.J. Mendes 2811 ( COI) ; Cuito-Cuanavale, Longa , Cuango , vale do Cuango , alt. 1370 m, 18 Mar. 1960, E.J. Mendes 3185 ( BR, P) ; Huambo, Mission de Humabo , Nov. 1942, C. Tisserant A310 ( COI) ; Chianga, alt. 1700 m, 11 June 1962, Teixeira & Andrada 6446 ( COI) ; Arredores de Nova Lisboa, Chiva ,alt. 1700 m, 19 Mar.1971, M. de Silva 3480 ( BR, COI) ; Huíla, Serra de Chella , aux environs de Huíla , alt. 1850 m, 1937, H.Humbert 16686 ( P) ; Entlang einem Bache auf dem Hochplateau von Bimbe bei Humpata , alt. 2300 m, 9 Sept. 1950, H. Hess 50/188 ( ZT) ; Lubango, Chipia , ao km 7 da picada para Missao do Munhino, 11 May 1971, A. Borges 248 ( BR, COI) ; Lunda, Vila Henrique de Carvalho , rio Chicapa , alt. 1100 m, 16 Apr. 1937, A.W. Exell & F.A. Mendon ҫa 636 & 644 ( COI) ; Malanje, Quimbango , Congolo , Reserca da Palanca Negra Gigante (ou Reserva do Luando ), 7 June 1970, G. Barbosa et al. 11963 ( COI) ; Uíge , near small lagoon, through which water flows, S6°1' E15°24',alt. 803 m, 25 Feb.2017, T. Lautenschläger 2017-02-139 & 2017-02-111 ( DR) . – DRC, Equateur, Ilema ( Terr.Coquilhat- ville ), 21 Mar. 1958, Èvrard 3748 ( BR) ; Haut-Katanga, Le long de la route Mitwaba – Manono ,à 11 km de Mitwaba – Sermikat, 21 Apr.1997, Symoens 3612 ( BR) ; Ituri, Nioka ( Mahagi ), alt. 1700 m, 29 July 1960, D. Froment 758 ( BR, P) ; Kinshasa, Route Soo-Ndunu , Maluku , 5 May 1971, H. Breyne 2190 ( BR) ; Kongo Central, Binza, Route de Ngidinga à Kimvula , Territoire de Madimba , 15 Feb. 1960, P. Compere 1479 ( BR) ; Kilenfu-Leg-Boko, S5°01' E15°11', 10 Feb. 2014, Nsimundele 2723 ( BR) ; Kwango, Nto Mbombo , terr. Popokabaka , 9 Jan. 1959, L. Pauwels 1208 ( BR) ; Tangi , alt. 700 m, Jan. 1930, J. Lebrun 127 ( BR) ; Lualaba, Shaba , Kolwezi – Luena , km 114 , Riv. Mutendele , 20 Jan.1986, Bamps & Malaisse 8222 ( BR) ; Environs de Kolwezi, vallée de la Kanamwamfwe , 23 Aug. 2004, Malaisse & Kisimba 134 ( BR) ; Sud-Kivu, Massif du Kahuzi , Env. du 43 km de la route Bukavu-Walikale, alt. 2200 m, 22 Apr. 1970, J. Lambinon 78/228 ( BR) ; Tanganyika, Kilunga ( Marungu ), Apr. 1945, L. Dubois 1416 ( BR) ; 3 km a l’W. de Kasiki, Plateau des Marungu , alt. 2000 m, 12 June 1969, S. Lisowski et al. 6139 ( BR) ; Mare Mufufu, Plateau des Marungu , alt. 1900 m, 14 June 1969, S. Lisowski et al. 6606 ( BR) .

Note — A very variable species with stems occasionally suppressed and dwarf forms (these show often suborbicular to elliptic leaves and a reddish colour). Hybridisation with D. elongata and D. affinis is possible. Plants in South Africa with suppressed stems ( D. madagascariensis var. major Burtt Davy ) were synonymized with D. curvipes Planch. and plants from southern Africa were synonymised with D. ramentacea Burch. ex DC. Both D. curvipes and D. ramentacea are now mostly accepted as separate taxa ( Robinson et al. 2017). The distinct diagnostic features of D. madagascariensis (reflexed leaves, strongly curved base of inflorescence; Fig. 10 ) make most of the specimens easy to determine. However, the species is known to be highly variable in height, stem length and leaf size and shape depending on the habitat and available nutrients ( Robinson et al. 2017). The dwarf form of D. madagascariensis (e.g., H. Breyne 4636) can be easily mistaken for D. burkeana or D. pilosa . To distinguish between these species leaf shape, seed shape and morphology and pollen morphology could be used. Furthermore, relatively large and robust specimens occur. Three large specimens are doubtfully determined as D. madagascariensis (partly H. Hess 50/188, A.W. Exell & F.A. Mendon ҫa 644 and 636) showing very large obovate to elliptic laminae, densely pilose stems, scapes and leaves and more or less erect to strongly curved inflorescences.

Figures

Fig. 10 Drosera madagascariensis DC. a. Leaf shape showing a slender, glabrous to pilose petiole and an obovate to spathulate lamina; b. general morphology: caulescent with spiral, reflexed leaves and laterally arising inflorescences; c. distribution according to the literature; d. province map of Angola and DRC with localities of examined herbarium specimens; e. pollen in tetrads with echinate, broadly conical sculpture elements in medium density. — Scale bars: a = 1 cm; b = 2 cm; e = 10 µm.