Lasianthus longifolius subsp. longifolius

Zhu, H., Roos, M. C. & Ridsdale, C. E., 2012, A taxonomic revision of the Malesian species of Lasianthus (Rubiaceae), Blumea 57 (1), pp. 1-102 : 55-58

a. subsp. longifolius

Lasianthus longifolius Wight (1846) 514; Hook.f.(1880) 187; King & Gamble (1904) 116; Ridl. (1923a) 164. —

Type: Kew Dist. 2936 ( Griffith s.n.) ( holo K), Peninsular Malaysia .

Treelets,c. 2 m high;branchlets robust,often compressed,c. 3–5 mm diam, glabrous. Leaves: blades obovate-oblong to lanceolate-oblong, 20– 33 by 6 –11 cm, coriaceous, glabrous above, rigid minute hairs on venation beneath and scabrous (asperate) when touching, apex cuspidate to cuspidate-acute, base cuneate, slightly asymmetric, midrib and nerves slightly prominent above, strongly prominent beneath, nerves 13–18 pairs, ascending at an angle of 60–70°, curved to the margin, nervules prominent on both surfaces, reticulate; petioles 5–10 mm long, glabrous, or sparsely ciliate hairs on the margin. Stipules broadly triangular or oblong-lanceolate, 6 –12 mm long, glabrous. Cymes sessile or very short tuberculate; bracts inconspicuous or fewer, small, ovate, hirsute, less than 3 mm long. Flowers sessile; calyx tube obconical, c. 2 mm long, glabrous, limb cupular, c. 2 mm long, glabrous, truncate or with 4–5 triangular teeth which are c. 0.5–1 mm long and sparsely ciliate at margin; corolla tube c. 5– 6 mm long, glabrous, lobes 4–6, lanceolate, c. 4–5 mm long, glabrous outside, densely floccose inside. Drupes subglobose, c. 5– 6 mm diam, glabrous, crowned by a usually truncate calyx limb, ridged; pyrenes 6, ridged on the abaxial face.

Distribution — Peninsular Malaysia and Indonesia ( Sumatra).

Note — Lasianthus longifolius differs from L. griffithii by having leaves with rigid minute hairs on venation beneath, oblong-lanceolate stipules not covering the flowers, without numerous filiform bracts except fewer very small ones, flowers with cupular calyx, drupes crowned by a cupular truncate or small dentate calyx limb.