Lasianthus barbatus 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 : 16

8. Lasianthus barbatus H.Zhu , sp. nov. — Fig. 3

Proximus L. glabro Ridl. , sed foliis lanceolatis, 1.3–2.5 cm latis, nervulis subtus conspicuis,parallelis atque stipulis et bracteis minoribus differt. —

Typus: T. Suppiah s.n. KEP 104817 ( holo L), Peninsular Malaysia, Kelantan, Ulu Sat FR. , in primary forest, 13 June 1968 .

Shrub, 2 mm high; branchlets terete, c. 2 mm diam, glabrous, brown. Leaves: blades lanceolate, 8 –12 by 1.3 –2.5 cm, subcoriaceous, glabrous except sparsely hirsute nerves beneath, apex caudate, aristate, arista 2 mm long, base acuminate to acute, midrib slightly depressed above, prominent beneath, glabrous, nerves flat above, prominent beneath, 5 – 6 pairs, ascending at an angle of 50–60°, curved to margin, sparsely hirsute beneath, nervules obscure above, conspicuous beneath, parallel, glabrous; petioles c. 5 mm long, glabrous. Stipules ovate-triangular to broadly triangular, 4–5 by 4 mm, glabrous except barbate margin. Inflorescences axillary, sessile; bracts ovate-triangular, glabrous except barbate margin, 4–5 by 2–4 mm; bracteoles ovate-triangular, glabrous except barbate margin. Flowers fascicular, sessile. Drupes subglobose, 4–5 by 4 mm, with 5 obtuse ridges, glabrous; calyx lobes persistent, lanceolate, 1 mm long, hirsute; pyrenes 4–5, smooth on the abaxial face, sulcate on the adaxial and the side faces in transverse section.

Distribution — Endemic to Peninsular Malaysia.

Habitat & Ecology — In primary forest. Fruiting in June.

Note — This species has stipules and bracts with barbate margins as L. glaber . It differs from the latter by having lanceolate leaves less than 2.5 cm broad, nervules conspicuous beneath, parallel, relatively small stipules and bracts; while L. glaber has elliptic-oblong leaves, 12–18 by 4–5.5 cm, nervules obscure on both surfaces, relatively large stipules and bracts. It is close to L. foxworthyanus , but differs from the latter by having glabrous branchlets and leaves, leaves lanceolate, nerves 5 – 6, stipules and bracts ovate-triangular, glabrous except barbate margins, drupes with 4–5 pyrenes.

Figures

Fig. 3 Lasianthus barbatus H.Zhu. a. Habit; b. detail of lower surface of leaf; c. stipule; d. bract; e. fruit; f. cross section of fruit (all: T. Suppiah s.n. KEP 104817, holo L).