Dissochaeta johorensis Furtado, Gard. Bull. Singapore 20: 110. 1963.

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

29. Dissochaeta johorensis Furtado, Gard. Bull. Singapore 20: 110. 1963. Map 19

Dissochaeta hirsuta auct. non Hook. f. ex Triana; King, J. Asiat. Soc. Bengal, Pt. 2, Nat. Hist. 69(2): 51. 1900; Ridl., Fl. Malay Penins. 1: 797. 1922. p.p., excl. type.

Type.

Malaysia. Johor: Gunong Panti, 1892, H.N. Ridley 4185 (holotype: SING n.v.; isotypes: BM [BM000944478]!, K [K000859526]!).

Description.

Climbing up to 4.5 m in height. Branchlets terete, 2-4 mm in diameter, densely covered with brown stellate-furfuraceous hairs and 1-2 mm long bristle hairs; nodes swollen, with interpetiolar ridge; internodes 3.5-7.5 cm long. Leaves: petioles terete, 6-10 mm long, densely covered with stellate-furfuraceous and bristle hairs; blades ovate or elliptic, 7-10 × 2.8-6 cm, membranous, base emarginate, margin entire, ciliate, apex acuminate, tip 1-1.5 cm long; nervation with 1 pair of lateral nerves and 1 pair of intramarginal nerves; adaxially hirsute to scabrid with scattered bristle hairs, abaxially densely covered with bristle hairs in most part, more densely so at midrib and margin. Inflorescences terminal, up to 25 cm long, many-flowered; main axis angular, densely covered with brown stellate-furfuraceous and bristle hairs; primary axes up to 21 cm long with 5 or 6 nodes, secondary axes 2-6 cm long with 1-3 nodes, tertiary axes up to 1 cm long with 1 node; bracts linear, ca. 4 mm long, densely covered with stellate-furfuraceous and bristle hairs; bracteoles linear, ca. 2 mm long, densely covered with stellate-furfuraceous and bristle hairs; pedicels densely covered with stellate-furfuraceous and bristle hairs, ca. 4 mm long in central flowers, 1-2 mm long in lateral flowers. Hypanthium suburceolate, 5-6 × 2-2.5 mm, densely covered with stellate-furfuraceous hairs and glandular bristle hairs, dark green; calyx lobes slightly triangular, 1-2 mm long, tips acute, densely bristly, pinkish; petal bud conical, 3-4.5 mm long, apex glabrous; mature petals obovate to oblong, 7-8 × ca. 3 mm, not-reflexed, base clawed, apex acute, glabrous, pink or violet. Stamens 8, subequal, filaments curved sideways, pale yellow; alternipetalous stamens with 6-7 mm long filaments, anthers lanceolate, sickle-shaped, thecae 10-11 mm long, apex rostrate, white-cream, pedoconnective 1-1.5 mm long, basal crests minute, triangular, ca. 0.5 mm long, lateral appendages paired, filiform, up to 3 mm long, cream; oppositipetalous stamens with 6-7 mm filaments, anther thick, S-shaped, thecae 9-10 mm long, white-cream, basal crests minute, laminar or spur-like, ca. 0.5 mm long, lateral appendages small, bifid, ca. 0.3 mm long or paired and filiform, 2-2.5 mm long. Ovary ⅔ of hypanthium in length, apex villous; style curved at end, 9-12 mm long, glabrous, white; stigma minute, capitate; extra-ovarial chambers 8, extending to the middle of the ovary. Fruits urceolate, 8-10 × 4.5-5 mm, sparsely stellate-furfuraceous and densely covered with glandular bristle hairs; calyx lobe remnants persistent, reflexed. Seeds ca. 0.5 mm long.

Distribution.

Peninsular Malaysia (Johor) and Sumatra (Riau Archipelago).

Ecology and habitat.

Edge of evergreen forest in open thickets and lowland forest at 10-200 m elevation.

Note.

Dissochaeta johorensis resembles D. rostrata in its indumentum of dense bristle hairs on most parts, but differs by its acute, triangular calyx lobes (vs. obtuse, ovate lobes) and urceolate fruits (vs. subglobose to ovoid fruits). The shape of the stamens and the appendages in both species are also different.

Specimens examined.

MALAYSIA. Johor: Kota Tinggi, Gunong Panti, 1892, H.N. Ridley 4185 (BM, K); Ibid., 1880, H. Kunstler 197 (K, P); Ibid., 200 m, 8 Apr 1977, J.F. Maxwell 77-181 (L); Ibid., 7 Feb 1978, J.F. Maxwell 78-31 (L); Ibid., 50 m, 8 Dec 1979, J.F. Maxwell 79-48 (L); Ibid., 4 Jan 1980, K. Bremer 1840 (K); Kluang FR., 60 m, 31 Jan 1966, F.S.P. Ng KEP 97965 (K); Ibid., 24 Nov 1967, Alphonso, Sanusi & Sidek S.197 (K, L); Endau Rompin, Kuala Jasin, 100 m, 1 Mar 1996, M.M.J. van Balgooy 7114 (L); Lombong FR, 30 m, 22 May 1959, H.M. Burkill HMB 1822 (K, L); Sungai Kayu, 9 Mar 1937, Kiah SFN 32357 (BM, K, PNH); Gunong Muntahak, 183 m, 3 Mar 1928, M. Nur SFN 19975 (BM, BO, K); Labis, Sungei Kinchin, 30 m, 25 Aug 1988, L.G. Saw FRI 36361 (L). INDONESIA. Riau Archipelago: Lingga Islands, Singkep Island, Kampung Raya, 10 m, 1 Aug 1919, H.A.B. Bünnemeijer 7096 (BO); Ibid., Manggu, 40 m, 2 Aug 1919, H.A.B. Bünnemeijer 7175 (BO); Ibid., Dabo, 40 m, 4 Aug 1919, H.A.B. Bünnemeijer 7276 (BO).

Figures

Map 19. Distribution of D. johorensis (●), D. latifolia (■) and D. leprosa (▲).