Dissochaeta pubescens (Merr.) Karton., 2018

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

42. Dissochaeta pubescens (Merr.) Karton. comb. nov. Map 24

Anplectrum beccarianum Cogn. in A.DC. & C.DC., Monogr. Phan. 7: 568. 1891. Type: Malaysia. Sarawak, O. Beccari PB 809 (lectotype, designated here: FI [FI008755, image seen]!; isolectotypes: BR [BR5188895, image seen]!, K [K000859574, K000859575]!).

Diplectria beccariana (Cogn.) Kuntze, Revis. Gen. Pl. 1: 246. 1891.

Dalenia furfuracea Ridl., Kew Bull. 1: 33. 1946. Type: Malaysia. Sarawak: Pengkulu Ampat, G.D. Haviland & C. Hose 144 (lectotype, designated by Nayar 1966, pg. 159: K [K000859506]!; isolectotype: BM [BM001190921, BM001190922]!, SING n.v.).

Dalenia beccariana (Cogn.) M.P.Nayar, Kew Bull. 20: 157. 1966.

Dalenia beccariana (Cogn.) M.P.Nayar var. matangensis M.P.Nayar, Kew Bull. 20: 158. 1966. Type: Malaysia. Sarawak: Matang, Aug 1905, H.N. Ridley 12259 (holotype: K [K000859571]!; isotype: SING n.v.).

Basionym.

Dalenia pubescens Merr., J. Straits Branch Roy. Asiat. Soc. 86: 338. 1922.

Type.

Malaysia. Sabah: Kiau, Mount Kinabalu, 4 Des 1915, M.S. Clemens 10301 (lectotype, designated here: A [A00072194, image seen]!).

Description.

Climbing up to 20 m in height; branchlets terete, 4-5 mm in diameter, covered with brown stellate-furfuraceous hairs; nodes swollen, with raised annular crest-like interpetiolar ridge, apex rounded, up to 6 mm high, densely covered with stellate hairs; internodes 8-21 cm long. Leaves: petioles terete, 15-35 mm long, densely brown stellate-furfuraceous; blades suborbicular, ovate to elliptic, (8 –)15– 30 × (4 –)10– 20 cm, subcoriaceous, base rounded to cordate, margin entire, apex acute or acuminate, tip 0.5-1 cm long; nervation with 1 or 2 pairs of lateral nerves and 1 pair of intramarginal nerves; adaxially glabrous, glossy green, abaxially densely covered with brown pubescent hairs. Inflorescences terminal, up to 80 cm long, many-flowered; main axis angular, densely covered with brown stellate hairs; primary axes 35-76 cm long with 6-10 nodes, secondary axes up to 18 cm long with 2-4 nodes, tertiary axes up to 4 cm long with 1 or 2 nodes, quarternary axes when developed up to 8 mm long with 1 node; bracts either crest-like, erect, as wide as the rachis, 2-3 mm high or somewhat ligulate, 1.5-2 mm long, both types caducous, oftenly seen only on the terminal cymules; bracteoles linear or ligulate, 1-2 mm long, caducous; pedicels densely stellate-furfuraceous, brown, 9-10 mm long in central flowers, 5-8 mm long in lateral flowers. Hypanthium campanulate to suburceolate, 6-10 × 4-6 mm, covered with stellate pubescent hairs; calyx lobes truncate, without 4 distinct tips, ca. 0.5 mm long, forming calyptra enveloping petal buds, calyptra conical, up to 9 mm long, with acute tip, densely brown pubescent; petal buds conical, 7-8 mm long, apex acute; mature petals ovate, 7-8 × ca. 4 mm, base clawed, apex acute to obtuse, white to pink or purple. Stamens 8, unequal, filaments straight, white; alternipetalous stamens staminodial with 4-5 mm long filaments, anthers rudimentary, thecae ca. 2 mm long, slender, basal crest triangular 1-1.5 mm long, lateral appendages paired, thin, flat, filiform, 4-5 mm long; oppositipetalous stamens with 4-5 mm long filaments, anthers thick, curved, hooked- or S-shaped, thecae 8-9 mm long, apex rostrate, yellow, basal crest shortly triangular, ca. 0.5 mm long, lateral appendages absent or minute points. Ovary ⅔ of hypanthium in length, apex glabrous; style 13-15 mm long, curved at the end, slender, glabrous, white; stigma minute; extra-ovarial chambers 4, oppositipetalous, reaching to the base of the ovary. Fruits ovoid-urceolate, rarely subglobose, 10-12 × 6-8 mm, brown stellate-pubescent; calyx lobes remnant persistent, erect. Seeds ca. 0.5 mm long.

Distribution.

Borneo.

Ecology and habitat.

Lowland dipterocarp forest or low montane forest, roadside along the forest edges, river banks or logged forests at 25-900 m elevation.

Vernacular name.

Akar (Sintang).

Note.

Dissochaeta pubescens is recognised by its robust leaf blades (up to 30 × 20 cm) and inflorescences (up to 80 cm long). The typical indumentum of most parts resembles that of D. axillaris and D. latifolia . In bud, the petals of D. pubescens are enclosed by a thin calyptra, which will fall off during anthesis. The calyptra is similar to that of D. pulchra . The epithet pubescens, the first available heterotypic synonym, is used here for the new combination name because an older Dissochaeta beccariana already exists.

Specimens examined.

MALAYSIA. Sabah: Labuk Sugut, Bukit Timimbang, 21 Sep 1984, Sigin et al. SAN 67567 (K); Lahad Datu, Ulu Segama, 14 Aug 1986, Joseph SAN 116983 (K); Nabawan, Nabawan–Pandewan Road, 12 Mar 1990, Sumbing SAN 128066 (K); Sandakan, Batu Lima, Sep-Dec 1920, M. Ramos BS 1585 (BM, BO, K, L, P); Labuk Road, 137 m, 8 Dec 1971, Dewol, Leopold & Shea SAN 74565 (K, L); Ranau, Mount Kinabalu, Kiau, 4 Dec 1915, M.S. Clemens 10301 (A); Ibid., Dallas, 914 m, 1 Oct 1931, J. Clemens & M.S. Clemens 26667 (BM, K, L); Ibid., J. Clemens & M.S. Clemens 30389 (K, L); Ibid., Ulu Tungud, Gunung Monkobo, 296 m, L.G. Saw et al. SAN 146684 (L). Sarawak: 26 Oct 1894, G.D. Haviland & C. Hose 144E (L); 1871, O. Beccari PB 809 (K); Kuching, Matang, Aug 1905, H.N. Ridley 12259 (K); Ibid., 17 Mar 1955, W.M.A. Brooke 9714 (L); Pengkulu Ampat, G.D. Haviland 144 (BM, K); Kapit, Balleh, Ulu Mujong, 26 Mar 1964, Asah ak Unyong S.21200 (K); Ibid., 17 Apr 1964, Othman bin Haron S.19946 (BO, K, L); Baram, Batang Tinjar, Ulu Sg. Sekiwa, 152 m, 1 Sep 1974, S. Tong S.35025 (K, L); Ibid., Mount Dulit, 300 m, 16 Aug 1932, P.W. Richards 1301 (K, L); Ibid., Ulu Sungai Melinau, 122 m, 24 Jun 1961, J.A.R. Anderson S.4071 (K, L); Bintulu, Ulu Segan, 244 m, 24 Aug 1968, Ilias Paie S.27216 (BO, K, L); Kapit, Bukit Raya, 518 m, 4 May 1969, E. Soepadmo & P.K. Chai S.28175 (K, L); Ibid., Pelagus, 7 Jul 1979, B. Lee S.40230 (K, L); Limbang, Ulu Mendamit, Sg. Ensungei, 14 Sep 1980, R. George et al. S.42897 (K, L); Lundu, Mount Poi, 1929, J. Clemens & M.S. Clemens 20270 (K); Miri, Gunong Mulu, Melinau Gorge, 375 m, 2 Feb 1978, C. Hansen 244 (K); Marudi, Pulong Tau, 15 May 2007, R.P. de Kok et al. S.97859 (K); Tatau, Batang Anap, 240 m, 12 Jun 1982, Abang Mochtar S.41775 (K, L); Betong, Bukit Sadok, 15 Oct 1982, Banyeng & Ilias Paie S.45092 (K, L); Sibu, Ulu Sungai Pasai, Bukit Tanggi, 50 m, 29 Mar 1992, P.C. Yii & Jegong S.64404 (K, L); Sri Aman, Batang Ai, 350 m, 12 Dec 1994, P.C. Yii et al. S.69527 (L); Batang Balui, Ulu Sungai Elyak, 950 m, 12 Mar 1989, P.C. Yii S.56745 (K); Ibid., P.C. Yii S.56746 (K); Tubau, Merurong, 16 Oct 1984, Othman et al. S.48949 (K); Ibid., Batu Laga, 960 m, 19 Mar 1989, P.C. Yii S.56899 (AAU, L); Ulu Simunjan, G. Angkong, 23 Sep 1975, Martin & Othman S.36955 (K, L). BRUNEI. Belait: Labi, Mendaram, 30 m, 20 Jun 1995, A. Kalat et al. BRUN 16786 (K, L). Temburong: Pagon, 150 m, 22 Jul 1990, K.M. Wong 1869 (K); Kuala Belalong, 25 m, 22 Jun 1989, P.C. Boyce et al. 392 (K, L). Tutong: Ulu Tutong, Bukit Bahak, 210 m, 17 Dec 1991, D.W. Kirkup et al. 578 (K). INDONESIA. Central Kalimantan: Barito Ulu, 25 May 1990, C.E. Ridsdale PBU 185 (BO, L). East Kalimantan: West Kutai, Long Liang Beng, 250 m, 1 Sep 1925, F.H. Endert 3060 (BO, K, L); Samarinda, ITCI concession area, 250 m, 7 Jun 1989, M.M.J. van Balgooy 5840 (L); Wanariset, Samboja-Semoi road, 50 m, 7 May 1991, Ambriansyah & Z. Arifin W728 (K, L). West Kalimantan: Pontianak, Bentiang, Gunung Bayuh, 750 m, 31 Oct 1980, G. Shea 27146 (BO, K, L); Sintang, Bukit Baka, Sungai Ella, 320 m, 21 Oct 1993, A.C. Church et al. 273 (BO, L).

Figures

Map 24. Distribution of D. pubescens (●), D. rectandra (■) and D. vacillans (▲).