Dissochaeta laevis Ohwi ex J.F.Maxwell, Gard. Bull. Singapore 33: 315, fig. 2. 1980 (" laeve").

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

30. Dissochaeta laevis Ohwi ex J.F.Maxwell, Gard. Bull. Singapore 33: 315, fig. 2. 1980 (" laeve"). Map 18

Type.

Indonesia. East Kalimantan: W. Koetai, Long Petah, 600 m elev., 10 Sep 1925, F.H. Endert 3127 (holotype: L [L0537281]!; isotypes: BO [BO1760872]!, K [K000859490]!).

Description.

Climbing up to 6 m in height. Branchlets terete, 3-4 mm in diameter, glabrescent; nodes swollen, with short flat crest-like interpetiolar ridge, margin often with minute bristles; internodes 5-6 cm long. Leaves: petioles terete, 8-10 mm long, glabrous, tessellate; blades ovate to ovate-elliptic, 6-12 × 2.3-5.5 cm, membranous, base rounded, margin entire, apex acuminate, tip 0.5-1 cm long; nervation with 1 pair of lateral nerves and 1 pair of intramarginal nerves; surfaces glabrous, basally with a pair of glandular patches abaxially. Inflorescences terminal and axillary, up to 11 cm long when terminal, up to 9 cm long when axillary, many-flowered; main axis glabrescent; primary axes up to 8 cm long with 3 or 4 nodes, secondary axes 2-4.5 cm long with 2 or 3 nodes, tertiary axes 0.6-1 cm long with 1 node; bracts linear, 1-2 mm long, stellate-furfuraceous; bracteoles subulate, 0.5-1 mm long, stellate-furfuraceous; pedicels stellate-furfuraceous, ca. 4 mm long in central flowers, 2-3 mm long in lateral flowers. Hypanthium cyathiform, cup-shaped, 3-4 × ca. 2 mm, glabrous; calyx lobes truncate, ca. 0.3 mm long, with 4 distinct undulations; petal bud conical, 2-3 mm long, apex narrowly acuminate, glabrous; mature petals ovate, ca. 5 × 2.5 mm, reflexed, base clawed, apex acuminate, glabrous. Stamens 8, subequal, filaments straight; alternipetalous stamens with 2.5-3 mm long filaments, anthers oblong or ovate, curved, sickle-shaped, thecae ca. 3 mm long, pedoconnective short, ca. 0.3 mm long, basal crest triangular or ligular with hastate base, ca. 1.5 mm long, lateral appendages absent or paired, filiform, up to 1.5 mm long; oppositipetalous stamens with 2-2.5 mm long filaments, anthers sickle- or S-shaped, thecae ca. 2.5 mm long, basal crest ligular, ca. 2 mm long, lateral appendages absent. Ovary half as long as hypanthium, apex glabrous; style straight, 7-8 mm long, glabrous; stigma minute; extra-ovarial chambers shallow. Fruits globose, 3-5 × 3-4 mm, glabrous; calyx lobe remnants persistent. Seeds ca. 0.5 mm long.

Distribution.

Borneo.

Ecology and habitat.

Mixed dipterocarp forest or heath forest at 600-800 m elevation.

Note.

A glabrous species with a pair of glandular patches near the base of the leaf blade on the abaxially surface, resembling D. beccariana , D. glabra , D. glandulosa and D. papuana . It differs from these taxa by the axillary inflorescences.

Specimens examined.

MALAYSIA. Sarawak: Belaga, Linau-Balui, Sungei Jelini, 800 m, 1 Sep 1978, B. Lee S. 39326 (K, L); Kapit, Batang Balui, Bukit Kumbong, 700 m, 27 Feb 1992, Runi et al. S.62014 (K, L). INDONEISA. East Kalimantan: West Kutai, Long Petah, 600 m, 10 Sep 1925, F.H. Endert 3127 (BO, K, L). West Kalimantan: Pontianak, Bentiang, Gunung Dawuh, 800 m, 29 Oct 1980, G. Shea 26846 (BO, L).

Figures

Map 18. Distribution of D. inappendiculata (●), D. laevis (■) and D. macrosepala (▲).