Lasianthus fasciculus H.Zhu, 2012

43. Lasianthus fasciculus H.Zhu View in CoL , sp. nov. — Fig. 14 View Fig

Proximus L. euneuro Stapf , sed floribus 5-meris, calycibus 3–4 mm longis, lobis calycis triangulatis 1–1.5 mm longis, foliis 10–15 cm longis, nervis 9–11-binatis et nervulis supra obscuris differt. —

Typus: Kessler PK 32 (holo L), Sumatra, Kabulaten Tapanuli Utara Tele, 1650 m alt., in primary forest, 2 Dec. 1988 .

Treelet, c. 4–5 m high; branchlets compressed at the youngest part, densely appressed-pubescent. Leaves: blades oblong, 10–15 by 3– 5 cm, subcoriaceous, glabrous above, pubescent venation beneath, apex acute, mucronate, base acute, margin recurved, midrib depressed above, strongly prominent beneath, nerves flat or slightly depressed above, prominent beneath, 9–11 pairs, ascending at an angle of 60–70°, curved to margin, nervules obscure above, prominent beneath, parallel; petioles 1–1.5 cm long, densely appressed-pubescent. Stipules triangular, c. 1 mm long, densely appressed-pubescent. Inflorescences sessile; bracts inconspicuous. Flowers fascicular, sessile; calyx campanulate, 2–4 mm long, densely pubescent, lobes 5, triangular, 1–1.5 mm long, pubescent except margins external surface, tube 1.5 –2 mm long, densely pubescent; corolla 6–7 mm long, lobes 5, triangular-lanceolate, c. 2 mm long, densely pubescent external surface, floccose internal surface, tube glabrous at the lower part. Fruits not seen.

Distribution — Indonesia (West Sumatra).

Habitat & Ecology — In montane forests between 1650 – 2300 m altitude. Flowering during December and February.

Additional specimen examined. W Sumatra, Gunung Rasam, H. Nagamasu 3691 (L).

Note — This species is closely related to L. euneurus , but differs from the latter by having 5-merous flowers, calyx 3–4 mm long with triangular, 1–1.5 mm long lobes, leaves relatively big, 10–15 by 3– 5 cm, with 9 –11 pairs of nerves, nervules obscure above. Lasianthus euneurus has 4-merous flowers, calyx 1–1.5 mm long with 4 minute teeth, leaves less than 10 cm long with 7–8 pairs of nerves, nervules conspicuous and prominent above.