Lasianthus myrtifolius subsp. vicarius, 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 : 64

b. subsp. vicarius H.Zhu , subsp. nov. — Fig. 26

A typo foliis majoribus oblongis apice abrupte acutis, calycibus et corollis extus glabris differt.Similis L. coriaceifolius H.Zhu ,sed nervulis foliorum parallelis, calycibus minoribus, lobis calycis triangularibus, drupis non conspicue porcatis, pyrenis abaxiali laevigatis differt. — Typus: Banying ak Nyudong S.19397 (holo L), Borneo, Naoung,Anap, 1150 m alt., in submontane heath forest, 11 Oct. 1963 .

Treelet, 5 – 6 m high; branchlets terete, robust, c. 2.5 mm diam, glabrous, darkish. Leaves: blades oblong, 4.5–7.5 by 2–3 cm, thickly coriaceous, glabrous, apex abruptly acute, margin recurved, base acute, midrib, nerves and nervules prominent on both surfaces, nerves 6 –8 pairs, nervules parallel; petioles c. 3 mm long, glabrous, darkish. Stipules triangular-subulate, 1.5 mm long, subglabrous. Inflorescences sessile; bracts small, ovate, 1 mm long or inconspicuous. Flowers sessile; calyx campanulate, 2 – 3 mm long, glabrous, darkish, lobes 4, triangular, c. 1 mm long; corolla 4–5 mm long, glabrous on external surface, darkish, lobes ovate-triangular, 1 mm long. Drupes subglobose, c. 4 mm diam, glabrous, crowned by calyx lobes; pyrenes 4, smooth on abaxial face, suborbicular in the transverse section.

Distribution — Borneo ( Sarawak).

Habitat & Ecology — Submontane heath forest or mossy forest on the summit over 1100 m altitude. Flowering and fruiting between May and October.

Additional specimen examined. Sarawak, Bantulu, E.F. Brunig S.8770

(K, L).

Note — This subspecies differs from the typical subspecies by having oblong leaves with abruptly acute apex, glabrous calyx and corolla external surface. The typical subspecies has ovate-lanceolate or ovate leaves with caudate-acuminate apex, pubescent calyx and corolla external surface. It differs from L. coriaceifolius by having leaves with parallel nervules, calyx relatively small (2– 3 mm long), calyx lobes triangular, drupes without conspicuous ridges, pyrenes smooth on abaxial face. Lasianthus coriaceifolius has leaves with conspicuously reticulate nervules, calyx 5 mm long, calyx lobes ovate-oblong, drupes with 8 acute ridges, pyrenes with ridges on the abaxial face.

Figures

Fig. 26 Lasianthus myrtifolius Ridl. subsp. vicarius H.Zhu. a. Habit with inflorescences; b. flower (all: Banying ak Nyudong S.19397, holo L).