Lasianthus phymatodeus H.Zhu, 2012

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 : 75

96. Lasianthus phymatodeus H.Zhu , sp. nov. — Fig. 31

Proximus L. kinabaluensis Stapf , sed foliis non brochidodromis, nervulis densis parallelis, drupis conspicue verrucosis, pyrenis 4 conspicue acute porcatis differt. —

Typus: Tong S.33878 ( holo L ; iso K), Sarawak, Lubok Antu , 3300 ft alt., in mossy forest, 13 Mar. 1974 .

Treelet, c. 4 m high; branchlets terete, slightly compressed in the youngest part, c. 1.5 mm diam, glabrous, brownish. Leaves: blades lanceolate to ovate-elliptic, 8 –12 by 2– 3.5 cm, coriaceous, glabrous on both surfaces, apex acuminate to slightly caudate, base acute to abruptly acute, midrib flat to slightly depressed above, prominent beneath, glabrous; nerves flat above, prominent beneath, 4–5 pairs, ascending at an angle of 50–60°, curved to margin, glabrous, nervules obscure above, conspicuous beneath, dense and parallel, glabrous; petioles 6 – 8 mm long, glabrous. Stipules triangular, 1.5 –2 mm long, puberulous, bristle at the internal base of stipules. Inflorescences sessile to subsessile; bracts inconspicuous. Flowers small; calyx campanulate, c. 1 mm long, sparsely puberulous or glabrous, with 4 minutely subulate teeth; corolla not seen. Drupes oblate-globose, c. 6 –7 mm diam, glabrous, strongly warty; pyrenes 4, with irregular sharp ridges on all sides from transverse section view.

Distribution — Borneo ( Sarawak, Lubok Antu district).

Habitat & Ecology — In mossy forest between 3300–4200 ft altitude. Flowering and fruiting in March.

Additional specimen examined. Sarawak, Lubok Antu district, Paul Chai S.33826 (K, L).

Note — This species is closely related to L. kinabaluensis , but differs from the latter by having leaves with dense and parallel nervules, without looped venation, drupes strongly warty and with 4 pyrenes, pyrenes with conspicuously irregular sharp ridges on all sides from cross section view. Lasianthus kinabaluensis has leaves with looped venation, nervules loose and reticulate, drupes slightly warty, usually with 3 pyrenes, pyrenes slightly warty from cross section view.

Figures

Fig. 31 Lasianthus phymatodeus H.Zhu. a.Habit; b. lower surface of leaf showing parallel nervules;c. fruit;d. cross section of fruit (all S. Tong S.33878, holo L).