Lasianthus linearifolius 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 : 55

70. Lasianthus linearifolius H.Zhu , sp. nov.

Similis L. angustifolius King & Gamble , sed ramulis et foliis glabris, foliis linearibus, lobis calycis triangularibus 4 differt. —

Typus: Beaman et al. 7783 ( holo L), Borneo, Sabah, Ranau , 750 m alt., in dipterocarp forest, on ultramafic soil, 8 Dec. 1983 .

Shrub, 1 m high; branchlets terete, slender, less than 1 mm diam, sparsely puberulous or glabrous. Leaves: blades linear, 10–14 by 0.9–1.8 cm, subcoriaceous, glabrous or except sparsely pubescent midrib beneath, apex long-caudate, margin slightly undulate, base acute, midrib slightly prominent above, conspicuously prominent beneath, nerves slender, slightly prominent above, prominent beneath, 10–16 pairs, ascending at an angle of 80–90°, curved near margin, going paralleling to margin for some distance and joining the nerves above, forming an obscure intramarginal vein, nervules obscure above, weakly prominent beneath, subparallel; petioles 3– 6 mm long, sparsely puberulous. Stipules small, subulate, c. 1 mm long, pubescent. Inflorescences sessile; bracts absent. Flowers fascicular, sessile; immature calyx campanulate, pubescent or glabrous, tube c. 1 mm long, lobes 4, triangular, up to 1 mm long; corolla pubescent on external surface. Drupes subglobose, with 4 obtuse ridges, c. 3 mm diam, puberulous or glabrous, crowned by 4 small triangular calyx lobes; pyrenes 4.

Distribution — Malaysia ( Sabah).

Habitat & Ecology — In dipterocarp forest of SE base of Mt Kinabalu on ultramafic soil. Flowering and fruiting in December.

Additional specimen examined. Sahab: Ranau, D. Andau 1049 (K).

Note — This species is characterized by its linear leaves. It differs from L. angustifolius by having almost glabrous branchlets and leaves, leaves linear, calyx with 4 triangular lobes. Lasianthus angustifolius has branchlets densely pubescent, leaves oblong-lanceolate, leaf midrib and nerves densely pubescent, calyx with 5 triangular teeth.