Drosera burkeana Planch.

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 : 7

3. Drosera burkeana Planch. — Fig. 5

Drosera burkeana Planch. (1848) 192; Oliv. (1871) 402; Diels (1906) 88; G.C.C. Gilbert (1951) 552; Keay (1954) 26; J.R. Laundon (1959) 2; (1970) 26; Oberm.(1970) 194;A.S.Rob. et al. (2017) 1338. —

Type: J. Burke s.n. (holo K), South Africa, Nordwest, Macalisberg .

Perennial herb (sometimes annual), acaulescent. Leaves in a basal rosette ( Fig. 5b ), held horizontally; stipules 2–3.5 by c. 1.5 mm, membranous, connate at the base, apex lacerated (3 or more teeth), ferrugineous; lamina suborbicular, obovate to spathulate, 2–10 by 2–9 mm, reddish, adaxial surface and margins bearing tentacles, abaxially pilose, rarely glabrous ( Fig. 5a ); petiole 2–25 by 0.5–1 mm, linear throughout, abruptly broadening into the lamina, reddish, pilose (or glabrous). Inflorescences cymose, with 3–12 flowers; peduncles 1–4 together, 4–33 cm long, arising laterally, ascending, glandular; bracts linear, spathulate to narrowly obovate, 1–2 mm long, glandular or glabrous; pedicels 2–12 mm long, glandular. Sepals 5, elliptic to obovate, 2–5.5 by 2–2.5 mm, apex acute or obtuse, serrated, surfaces glandular (especially adaxially). Petals 5, obovate, 5–7 by 2–4 mm, pink to purple or white. Stamens 5, filaments 3–5 mm long, same colour as petals, anthers yellow. Pollen in tetrads, yellow, tetrads c. 40–46 µm diam, single grains c. 30–35 µm diam, pollen grains echinate ( Fig. 5e ), echini narrowly conical, c. 2 mm long, high density of echini, with short gemmate to clavate sculptural elements between echini. Pistil: ovary subglobose to obovate, 1.5–3.5 by 1–2.5 mm, glabrous, green; styles 3, 4–5 mm long, bipartite to the base, branches slender, curved upwards. Seeds ovoid, 0.3–0.4 by 0.15–0.2 mm, black, testa reticulate.

Distribution — Angola, Botswana, Burundi, Congo, DRC, Kenya, Lesotho, Madagascar, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Uganda, Zambia, Zimbabwe ( Fig. 5c ).

Habitat & Ecology — Grows on loam, sand and peat, sea- sonally to perennially wet spots.

Additional specimens (see Fig.5d for province map). ANGOLA, Benguela, Feuchte Wiese bei Humpata,alt. 1900 m, 9 Sept. 1950, H. Hess 50/ 254 ( ZT); Cuanza Sul, zona de Cassongue estrada em direc ҫão de Kahumbi,após do rio Cuvele femea, Inselberg, alt. 1580 m, 1 Apr. 2007, T. Leyens 402 ( FR); Cunene, Cuvelai,a cerca de 20 km para Cassinga, 22 July 1971, R. Santos 2918 ( COI); Huambo, Huambo, 1923, H. Vanderyst 13125 ( BR); près de la mission de Huambo, Aug. 1942, C. Tisserant A94 ( COI); 1 km W der prot. Mission von Elende, Cuma, alt. 1350 m, 25 July 1961, J.B. Damann 3099 ( ZT); Chianga, alt. 1700 m, 11 June 1962, Teixeira & Andrada 6445 ( COI); Huíla, Serra de Chella, aux environs de Humpata, alt. 2000–2200 m, 1937, H. Humbert 16650 (P); Humpata, Chongorola, rio Nene, pâtanos, 20 June 1937, A.W. Exell & F.A. Mendon ҫa 2989 ( COI); Sá da bandeira, Jau, Can- galongue, 3 Oct. 1965, C. Henriques 763 ( COI); Lunda , 100 km norte de Muconda, 12 Aug. 1927, Carrisso & Mendon ҫa 221a ( COI); Rio Caunhango junto da estrada Mucango a Casage, 16 Aug. 1927, Carrisso & Mendon ҫa 264 ( COI). – DRC, Haut-Katanga, 6.3 km au NNE du Peste de Katshupa, Plateau des Kundelungu, alt. 1580 m, 3 Aug. 1966, F. Malaisse 4490 ( BR); 7 km au N du Peste de Katshupa, Plateau des Kundelungu, alt. 1680 m, 1966-08-04, F. Malaisse 4504 ( BR); 6 km à l’WNW de la touree Oee de la Lut., Plateau des Kundelungu, alt. 1675–1680 m, 25 Mar. 1969, S. Lisowski et al. 3975 & 3453 ( BR); Haut-Katanga/ Haut-Lomami, Parc National de l’Upemba,route automobile pour le Shinkulu,alt. 1450 m, 21 May 1948, G.F. de Witte 03862 ( BR); Parc National de l’Upemba, 24 Sept. 1949, G.F. de Witte 07541 ( BR); Lualaba, Dilolo, Sept. 1931, Overlaet 1239 ( BR); Biano, S10°16' E26°03', alt. 1575 m, 23 May 1952, A. Schmitz 3918 ( BR).

Figures

Fig. 5 Drosera burkeana Planch. a. Leaf shape with a linear petiole that broadens abruptly into the suborbicular to spathulate lamina; b. general morphology: acaulescent, leaves in a rosette and laterally arising, glandular-pubescent inflorescences; c. distribution (grey) according to the literature; d. province map of Angola and DRC with localities of examined herbarium specimens; e. pollen occurs in tetrads with echinate, narrowly conical sculpture elements in high density. — Scale bars: a = 1 cm; b = 2 cm; e = 10 µm.