Lasianthus undulatus H.Zhu, 2012

126. Lasianthus undulatus H.Zhu View in CoL , sp. nov. — Fig. 39 View Fig

Similis L. clementis Merr. , sed ramulis dense tomentosis, foliis oblongi-lan- ceolatis rugosis margine undulatis,nervis 10–13-binatis, nervulis conspicue reticulatis et calycis limbis campanulatis differt. — Typus: Van Steenis 9886 (holo L; iso K), Sumatra, Atjeh, Gajalanden, 1100 m alt., in forest ridges, 20 Mar. 1937 .

Shrub, 4 m high; branchlets terete, c. 2 mm diam,densely brownish tomentose. Leaves: blades oblong-lanceolate, 6 –11 by 2– 3 cm, chartaceous to subcoriaceous, puberulous or glabrescent above, puberulous beneath, rugose on both surfaces, apex acute or caudate-cuspidate, mucronate, margin recurved, base acute or abruptly acute, rugose and more or less undulate, midrib flat or slightly prominent and hirsute above, conspicuously prominent and densely hirsute beneath, nerves slender, slightly prominent and sparsely hirsute above, conspicuous and densely hirsute beneath, 10–13 pairs, ascending at an angle of 70–80°, curved to the margin, nervules obscure above, conspicuous beneath, reticulate; petioles c. 2 mm long, densely tomentose. Stipules subulate-triangular, 2 – 3 mm long, densely tomentose. Inflorescences axillary, sessile; bracts absent. Flowers fascicular, sessile; calyx 2 mm long, pubescent on the external surface, tube obconical, c. 1 mm long, limb campanulate, lobes 5, triangular or subulate, c. 0.8 mm long; corolla up to 5 mm long, puberulous external surface, lobes 5, oblong-lanceolate, c. 2 mm long; stamens 5, filaments c. 0.8 mm long; anthers oblong, c. 0.8 mm long; ovary with 5 locules. Mature drupes not seen. Immature drupes subglobose, subglabrous, smooth; pyrenes 5, smooth on the abaxial face.

Distribution — Endemic to Sumatra.

Habitat & Ecology — Montane forest between 1100–1500 m altitude. Flowering and fruiting between February and June.

Additional specimens examined. N Sumatra,Atjeh, De Wilde et al. 14766

(K, L), 18625 (K, L).

Note — This species is similar to L. clementis , but differs from the latter by having densely tomentose hairs on branchlets; leaves oblong-lanceolate, rugose, undulate at margin, nerves 10–13 pairs, nervules conspicuously reticulate; calyx with a campanulate limb. Lasianthus clementis has appressed-pubescent branchlets; leaves ovate-lanceolate, smooth on surfaces and at margin; nerves 4–5 pairs; nervules subparallel; calyx without a campanulate limb.