Dissochaeta micrantha (Veldkamp) 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

37. Dissochaeta micrantha (Veldkamp) Karton. comb. nov. Map 21

Diplectria glabra (Merr.) M.P.Nayar var. micrantha (Veldkamp) J.F.Maxwell, Gard. Bull. Singapore 33: 313. 1980.

Basionym.

Diplectria micrantha Veldkamp, Blumea 24: 422, fig. 5B. 1978.

Type.

Malaysia. Sabah: Ranau District, Mount Kinabalu, Sosopodon, 4720 ft. elev., 30 Jan 1962, I.H. Sario SAN 28959 (holotype: L [L0008871]!; isotypes: K [K000859550]!, SAN n.v.).

Description.

Branchlets terete, 3-4 mm in diameter, glabrous; nodes swollen, with prominent annular, 2-3 mm wide, crest-like interpetiolar ridge, margin with 3-5 mm long simple bristles; internodes 6-12 cm long. Leaves: petioles terete, 5-10 mm long, glabrous to nearly furfuraceous and dorsally with bristle hairs; blades ovate, 6.5-9 × 3.5-5 cm, subcoriaceous, base cordate, margin entire, apex acuminate, tip 0.5-1 cm long; nervation with 1 pair of lateral nerves and 1 pair of intramarginal nerves; adaxially glabrous, abaxially glabrous except scattered stellate hairs on the nerves. Inflorescences terminal, up to 25 cm long, many-flowered; main axis angular, glabrous; primary axes up to 23 cm long with 7-9 nodes, secondary axes 8-10 cm long with 5-7 nodes, tertiary axes up to 1.5 cm long with 1 or 2 nodes, quarternary axes when developed up to 0.5 cm long with 1 node; bracts linear or ligular, 3-4 mm long, glabrous, caducous; bracteoles subulate, 1-2 mm long, glabrous; pedicels stellate-furfuraceous, 2-3 mm long in central flowers, ca. 1 mm long in lateral flowers. Hypanthium urceolate, ca. 3 × 1-1.5 mm, glabrous; calyx lobes truncate, ca. 0.3 mm long, apex with 4 minute points; petal buds conical, 1-1.5 mm long; mature petals suborbicular, 2-2.5 × ca. 2 mm, reflexed, base clawed, apex acute, pink. Stamens 8, unequal, filaments straight; alternipetalous stamens staminodial, with ca. 1 mm long filaments, thecae rudimentary, ca. 0.5 mm long, slender, terete, basal crest triangular, thin, ca. 1 mm long, apex erose, base with a small auricle, lateral appendages absent; oppositipetalous stamens with 1-2 mm long filaments, anthers thick, oblong, thecae 2-2.5 mm long, white, basal crest keels bifid, ca. 0.2 mm long, lateral appendages bifid, ca. 0.3 mm long. Ovary ⅔ of hypanthium in length, apex glabrous; style 3-4 mm long, glabrous; stigma minute, capitate; extra-ovarial chambers 4, oppositipetalous, extending to ⅓ of the ovary. Fruits subglobose, 4-5 × ca. 4 mm, glabrous; calyx lobe remnants persistent. Seeds ca. 0.5 mm long.

Distribution.

Borneo (Sabah and North Kalimantan).

Ecology and habitat.

Montane forest on river banks or in open places at 1100-1400 m elevation.

Note.

The desciption of the flowers is based on a bud only since mature flowers are still unknown. This species is restricted to the montane forests of Mount Kinabalu, Sabah and Kayan Mentarang, North Kalimantan.

Specimens examined.

MALAYSIA. Sabah: Ranau, Mt. Kinabalu, Sosopodon, 1440 m, 30 Jan 1962, I.H. Sario SAN 28959 (K, L); Ibid., Tenompok, 1500 m, 29 Feb 1932, J. Clemens & M.S. Clemens 28588 (BM, K); Ibid., May 1932, J. Clemens & M.S. Clemens 30341 (K); Ibid., between Tenompok and Kundasan, 1400 m, 15 Jul 1957, J. Sinclair et al. 9235 (L); Ibid., Sungai Mamut, 1200-1400 m, 15 Feb 1969, S. Kokawa & M. Hotta 5798 (L). INDONESIA. North Kalimantan: Krayan, Kayan Mentarang, Long Bawan, 1100 m, 29 Jul 1981, M. Kato et al. B-10105 (BO, L).

Figures

Map 21. Distribution of D. micrantha (■), D. nodosa (●) and D. papuana (▲).