Dissochaeta griffithii (M.P.Nayar) 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

24. Dissochaeta griffithii (M.P.Nayar) Karton comb. nov. Map 15

Dissochaeta annulata Hook. f. ex Triana var. griffithii (M.P.Nayar) J.F.Maxwell, Gard. Bull. Singapore 33: 313. 1980.

Basionym.

Macrolenes griffithii M.P.Nayar, J. Jap. Bot. 55: 47. 1980.

Type.

Malaysia. Malacca, W. Griffith KD 2269 (holotype: K [K001096571]!).

Description.

Branchlets terete, 3-4 mm in diameter, densely covered with brown stellate-furfuraceous hairs and simple dark, 2-3 mm long bristle hairs; nodes swollen, with distinct interpetiolar ridge; internodes 4-5.5 cm long. Leaves: petioles terete, 3-6 mm long, densely covered with brown stellate-furfuraceous hairs and simple dark, 2-3 mm long bristle hairs; blades ovate or ovate-oblong, 6-10 × 2.5-3.5 cm, subcoriaceous, base cordate, margin entire, apex acuminate, tip ca. 0.5 cm long; nervation with 1 pair of lateral nerves and 1 pair of intramarginal nerves; adaxially glabrous, dark green, abaxially densely covered with brown stellate-furfuraceous hairs. Inflorescences terminal or in upper leaf axils, up to 12 cm long when terminal, many-flowered, 3-4 cm long when axillary, with 1-3 flowers; main axis angular, densely covered with brown stellate-furfuraceous hairs and simple dark bristle hairs; primary axes 8-9 cm long with 3 or 4 nodes, secondary axes 1-2 cm long with 1 or 2 nodes, tertiary axes when developed ca. 0.5 cm long with 1 node; bracts oblong to lanceolate, 15-20 × 6-8 mm, densely brown stellate-furfuraceous; bracteoles lanceolate, 10-15 × ca. 2 mm, densely brown stellate-furfuraceous; pedicels densely covered with bristle hairs, ca. 1 mm long in central flowers, ca. 0.5 mm long or nearly sessile in lateral flowers. Hypanthium campanulate, 8-10 × 5-7 mm, densely covered with stellate-tomentose hairs and simple 3-5 mm long eglandular bristle hairs; calyx lobes triangular with acute tips, 2.5-3 × 2-3 mm; petal buds conical, 6-8 mm long, apex acute; mature petals ovate to oblong, 11-14 × 6-7.5 mm, reflexed, base clawed, apex obtuse, glabrous with ciliate margin, pink. Stamens 8, unequal, filaments curved sideways, light yellow; alternipetalous stamens with 12-14 mm long filaments, anthers lanceolate, slender, sickle-shaped, thecae 16-18 mm long, apex rostrate, pedoconnective 4-5 mm long, basal crest entire, erose or bifid, 1-2 mm long, lateral appendages paired, filiform, 6-7 mm long; oppositipetalous stamens with 11-12 mm long filaments, anthers hook- or S-shaped, thecae 10-12 mm long, basal crest ligular, obtuse or erose, ca. 1 mm long, lateral appendages paired, filiform, 4-5 mm long, yellow. Ovary ¾ of hypanthium in length, apex villous; style 22-24 mm long, curved sideways in direction opposite to the filaments, curved at the tip, glabrous; stigma minute; extra-ovarial chambers 8, extending to near the base of the ovary. Fruits ovoid to nearly subglobose, 13-15 × 5-8 mm, densely covered with stellate-tomentose hairs and simple 3-5 mm long eglandular bristle hairs; calyx lobe remnants persistent. Seeds ca. 0.5 mm long.

Distribution.

Peninsular Malaysia.

Ecology and habitat.

Lowland primary forest in open places at 27-120 m elevation.

Note.

1. The appearance of the hypanthium with distinct calyx lobes was recognised by Nayar (1980) as typical for Macrolenes , but the character of the stamens and its appendages closely resemble Dissochaeta , with a pair of filiform appendages on the alternipetalous stamens and not fimbriate appendages as is common in Macrolenes . This species resembles Macrolenes echinulata (Naudin) Bakh. f. which is also distributed in Peninsular Malaysia but differs in lacking paired hair cushions at the base of the leaves abaxiallyly (present in M. echinulata ) and only has one pair of lateral appendages at alternipetalous stamens (which are fimbriate in M. echinulata ).

2. Maxwell (1980b) reduces this species to a variety of D. annulata based on the similarity in the number and shape of the stamens. Dissochaeta griffithii differs from D. annulata by its distinct triangular calyx lobes (truncate in D. annulata ) and hypanthium with dense simple eglandular bristle hairs (lacking or with scattered glandular bristle hairs in D. annulata ).

Specimens examined.

MALAYSIA. Malacca: W. Griffith KD 2269 (K); A.C. Maingay KD 784 (K). Negeri Sembilan: Jelebu, Pasoh Forest Reserve, 80-120 m, 9 Jun 1996, E.C. Gardette 1989 (K, L). Pahang: Tasek Bera, 76 m, 28 Oct 1961, W.L. Chew & M. Noor 270 (K, L). Selangor: Rantau Panjang, 27 m. 29 Sep 1927, E.J. Strugnell 13965 (K).

Figures

Map 15. Distribution of D. glandiformis (●), D. glandulosa (■) and D. griffithii (▲).