Dissochaeta rostrata Korth. in Temminck, Verh. Nat. Gesch. Ned. Bezitt., Bot. 239. 1844.

Kartonegoro, Abdulrokhman, Veldkamp, Jan Frits, Hovenkamp, Peter & Welzen, Peter van, 2018, A revision of Dissochaeta (Melastomataceae, Dissochaeteae), PhytoKeys 107, pp. 1-178 : 1

46. Dissochaeta rostrata Korth. in Temminck, Verh. Nat. Gesch. Ned. Bezitt., Bot. 239. 1844. Map 25

Anplectrum korthalsii Triana, Trans. Linn. Soc. London 28: 85. 1872. Type: Based on Dissochaeta rostrata Korth.

Dissochaeta hirsuta Hook. f. ex Triana, Trans. Linn. Soc. London 28: 83. 1872. Type: Malaysia. Sarawak: Labuan, J. Motley s.n. (holotype: K [K000859629]!).

Diplectria korthalsii (Triana) Kuntze, Revis. Gen. Pl. 1: 246. 1891.

Dissochaeta setosa O.Schwartz, Mitt. Inst. Allg. Bot. Hamburg 7: 250. 1931. Type: Indonesia. West Kalimantan: Lebang Hara 150 m elev., 1 Jan 1925, J. Winkler 1167 (lectotype, designated here: HBG [HBG522818, image seen]!; isolectotypes: BO [BO1747972]!, HBG [HBG522819, HBG522820, images seen]!, L [L0008893]!).

Macrolenes ruttenii Bakh. f., Contr. Melastom.: 210. 1943. Type: Indonesia. East Kalimantan: Samarinda, Soengei Boengaloen, 12 Nov 1911, L.M.R. Rutten 535 (holotype: U [U0004012]!).

Dissochaeta rostrata Korth. var. hirsuta (Hook. f. ex Triana) J.F.Maxwell, Gard. Bull. Singapore 33: 319. 1980.

Dissochaeta rostrata Korth. var. setosa (O.Schwartz) J.F.Maxwell, Gard. Bull. Singapore 33: 321. 1980.

Type.

Indonesia. South Kalimantan: G. Prarawin, P.W. Korthals s.n. (lectotype, designated here: L [L0729470]!; isolectotype: L [L0729469]!).

Description.

Climbing up to 8 m in height. Branchlets terete, 2-4 mm in diameter, sparsely brown puberulous and densely covered with 1-2 mm long bristle hairs; nodes swollen, with interpetiolar ridge, thickly covered with bristle hairs; internodes 7-7.5 cm long. Leaves: petioles terete, 8-18 mm long, densely covered with bristle hairs; blades ovate, ovate-elliptic to elliptic, 7.5-14 × 3.8-9 cm, membranous, base emarginate, margin entire, apex acuminate, tip ca. 1 cm long; nervation with 2 pairs of lateral nerves and 1 pair of intramarginal nerves; adaxially hirsute, covered with scattered bristle hairs, abaxially densely covered with bristle hairs in most part, more densely so at midrib and margins. Inflorescences terminal, up to 25 cm long, many-flowered; main axis terete, densely covered with bristle hairs; primary axes up to 15 cm long with 4 nodes, secondary axes 2-4 cm long with 2 or 3 nodes, tertiary axes up to 1 cm long with 1 node; bracts oblong-lanceolate, 15-17 × ca. 5 mm, sparsely stellate puberulous and with dense bristle hairs, thin; bracteoles oblong, 4-7 × 2-3 mm, sparsely stellate puberulous and margin with dense bristle hairs; pedicels densely stellate-furfuraceous and with bristle hairs, 2-3 mm long in central flowers, 1-2 mm long in lateral flowers. Hypanthium campanulate or suburceolate, ca. 4 × 2.5-3 mm, densely covered with brown stellate hairs and bristle hairs; calyx lobes subtriangular or oblong, 2-2.5 mm long, apex obtuse, densely bristly at margin, pinkish to purplish; petal bud conical, 2-3.5 mm long, apex bristly; mature petals obovate or suborbicular, 5-6 × 4-5 mm, not-reflexed, base clawed, apex rounded, glabrous, veined, purple, light purple or pink. Stamens 8, subequal, filaments curved sideways, pale yellow; alternipetalous stamens with 4-5 mm long filaments, anthers lanceolate, sickle-shaped, thecae 5-6 mm long, apex rostrate, purple, pedoconnective ca. 2 mm long, basal crests minute, thin, ca. 0.5 mm long, lateral appendages paired, wavy, filiform, 1-2 mm long, white; oppositipetalous stamens with 4-5 mm long filaments, anthers thick, S-shaped, thecae 4-5 mm long, basal crest minute, ca. 0.5 mm long, lateral appendages paired, filiform, ca.1 mm long, white. Ovary ⅔ of hypanthium in length, apex villous; style curved at end, 10-11 mm long, glabrous, white; stigma minute, capitate; extra-ovarial chambers 8, extending to the middle of the ovary. Fruits subglobose or ovoid, 5-6 × 3-5 mm, densely covered with bristle hairs; calyx lobe remnants persistent, reflexed. Seeds ca. 0.5 mm long.

Distribution.

Borneo.

Ecology and habitat.

In mixed lowland dipterocarp forest, open areas at margin of forest and in riverine forest at 50-200 m elevation.

Vernacular name.

akar kemunting (Iban).

Notes.

1. Dissochaeta rostrata can easily be distinguished from other species with a bristly indumentum by its oblong-lanceolate bracts and bracteoles and subtriangular-oblong calyx tube.

2. The type collection (Korthals s.n.) from Leiden is only vegetative with mature leaves. The type of D. hirsuta (Motley s.n.) from Kew consists of a fruiting branch with mature leaves. The appearance of both is similar (shape and indumentum on the leaf blades), therefore we consider them to indicate the same species and we synonymise D. hirsuta with D. rostrata , an action following Veldkamp et al. (1979).

3. Dissochaeta setosa (type Winkler 1167), which is also limited to Borneo, has fruits that are similar to D. hirsuta with the distinct subtriangular-oblong calyx lobe remnants, hence we also included D. setosa in the species concept of D. rostrata .

4. Maxwell (1980b) recognised several species with a bristly indumentum as varieties of D. rostrata and made the species concept of the latter much wider. Here we consider them to represent distinct species: D. alstonii , D. densiflora , D. floccosa , D. horrida , D. macrosepala , D. malayana and D. porphyrocarpa .

Specimens examined.

MALAYSIA. Sarawak: Parai, 11 Dec 1892, G.D. Haviland 2036 (BM, K); Bintulu, Bukit Urang, 30 m, 7 Dec 1959, F. Brunig S.11981 (K); Kuching, E. Bartlett s.n. (BM); Lubok Antu, River Delok, Nanga Sumpa, 150 m, 27 Feb 1993, Christensen 1244 (K), Lubok Antu, Lanjak Entimau, 14 Mar 1974, P.K. Chai S.33819 (K); Kapit, Ulu Katibas, Sg. Joh, 110 m, 27 Jun 1993, A. Zainudin 4535 (L); Ibid., 150 m, 15 Nov 1997, K.G. Pearce et al. ITTO/BB 0431 (BO); Lawas, 22 May 1955, W.M.A. Brooke 10034 (BM, L); Lundu, Mt. Gading, 100 m, 19 Jul 1963, W.L. Chew 597 (K, L); Marudi, Long Tukan, 13 Mar 1972, Othman, Jugah & Anyie S.31862 (K, L); Miri, Lambir National Park, 8 May 1966, Banyeng ak Nudong S.25084 (BO, K, L), Ulu Sungei Lepoh, 18 Sep 1978, R. George S.40264 (L); Labuan, J. Motley s.n. (K); Niah, Niah River, 4 Apr 1979, P.C. Yii S.40124 (L). BRUNEI. Belait: Jalan Merangking-Buau, 10 Aug 1991, N. Nangkat 251 (K, L). Temburong: Batu Apoi, Selapon, 30 m, 27 Jan 1994, M.J.E. Coode et al. 7912 (L). INDONESIA. Central Kalimantan: Sungai Mentaya, 50 m, 1 Aug 1993, P. Wilkie 93374 (BO, E, K, L); Ibid., Tuke P1 1000 (L); Ibid., Tuke P5 1010 (L); Kapuas, Kayu Mas, 130 m, 24 Apr 1979, P.J.A. Kessler et al. 1461 (BO, L); Sampit River, Kuala Kuayan, 20 m, 1 Aug 1953, A.J.G.H. Kostermans 8045 (BO, L); Ibid., 27 Nov 1982, J.J. Afriastini 427 (BO); Ibid., Permantang, 50 m, 27 Jan 1954, A.H.G. Alston 13375 (BM); Ibid., 4 Apr 1984, C. Hansen 1366 (L); Bukit Raya, Tumbang Samba, 200 m, 27 Nov 1982, J.P. Mogea & W.J.J.O. de Wilde 3716 (BO, L); Ibid., 19 Dec 1982, H.P. Nooteboom 4370 (BO, L); Ibid., Batu Badinding, 23 Dec 1982, J.P. Mogea & W.J.J.O. de Wilde 4376 (BO, L); Ibid., Tumbang Tubus, 150 m, 6 Jan 1983, J.F. Veldkamp 8076 (BO, L). East Kalimantan: Sangata, Mentoko River, 300 m, 24 Jan 1979, R. Leighton 433 (L); Sebulu, 10 Aug 1973, K. Kartawinata 1185 (BO, L); Ibid., 27 Dec 1978, G. Murata et al. B-459 (BO, L); Road Kenangan to Gunung Meratus, 400 m, 27 Mar 1995, P.J.A. Kessler et al. 913 (P); Samarinda, Bengalon, 12 Nov 1911, L.M.R. Rutten 535 (U); West Kutai, Long Petah, 450 m, 16 Sep 1925, F.H. Endert 3360 (BO). South Kalimantan: Mount Prarawin, P.W. Korthals s.n. (L). West Kalimantan: Sintang, 150 m, 11 Apr 1994, U.W. Mahyar et al. 832 (BO, L); Ibid., Sungai Posang, 110 m, 30 Apr 1994, U.W. Mahyar et al. 1229 (BO, L); Ibid., Tegua Tibun, 75 m, 16 Oct 2000, Albertus & K. Sidiyasa 2236 (L); Lebang Hara, 150 m, 1 Jan 1925, J. Winkler 1167 (BO, L); Sanggau, Noyan, Ngira, 20 Feb 1994, De Jong 749 (BO, L); Katingan-Seruyan, 213 m, 26 Jul 2011, R. Susanti et al. 264 (BO).

Figures

Map 25. Distribution of D. rostrata (●), D. rubiginosa (▲) and D. sagittata (■).