Lasianthus bruneensis 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 : 25

17. Lasianthus bruneensis H.Zhu , sp. nov. — Fig. 8

Proximus L. subaureo Craib ,sed foliis basi rotundatis conspicue asymmetricis,stipulis minoribus 1 mm longis atque calycibus dentatis differt. —

Typus: Prance et al. 30620 (holo L; iso K), Brunei, Bukit Belalong, 909 m alt., in lower montane forest around summit, 23 Feb. 1992 .

Treelet, 2 m high; branchlets terete, puberulous, glabrescent or glabrous. Leaves: blades linear-lanceolate to oblong-lanceolate, 8–14 by 1.5–3 cm, coriaceous, glabrous or sparsely pu- berulous on leaf nerves beneath, apex attenuate to acuminate or caudate, margin recurved, base rounded, asymmetric, midrib conspicuously prominent on both surfaces, nerves flat above, prominent beneath, 6–7 pairs, ascending at an angle of 75–85°, curved to the margin, nervules conspicuous beneath, reticulate; petioles nigrescent, 1 cm long, sparsely puberulous. Stipules very small, triangular, 1 mm long, puberulous. Inflorescences sessile or short tuberculate, bracts inconspicuous. Flowers in fascicles sessile; calyx campanulate, 2 by 2 mm, puberulous, limb with 5 subulate-triangular 0.5 mm long teeth; corolla not seen. Drupes c. 4 mm diam, subglobose, subglabrous, black, crowned by persistent small subulate-triangular calyx teeth; pyrenes 4–5, slightly rugose on the abaxial face, triangular in transverse section, with thickened wall.

Distribution — Brunei.

Habitat & Ecology — In lower montane forest between 800 –1160 m altitude. In sandstone soil. Flowering and fruiting between October and February.

Additional specimens examined. Brunei, Bukit Tudal, Davis A.P. 481.

Note — This species is close to L. subaureus . It differs from the latter by having leaves with rounded and asymmetric bases, very small stipules, calyx not cupular, calyx limb with subulate-triangular teeth. Lasianthus subaureus has leaves with acute to acuminate base, stipules 3 mm long, calyx cupular, with truncate limb.

Figures

Fig. 8 Lasianthus bruneensis H.Zhu. a. Habit with inflorescences; b. lower surface of leaf showing reticulate nervules; c. detail of node showing stipule and axillary inflorescences; d. fruit (all: G.T. Prance et al. 30620, holo L).