Lasianthus longibracteatus H.Zhu, 2012

71. Lasianthus longibracteatus H.Zhu View in CoL , sp. nov. — Fig. 21 View Fig

Proximus L. rhinocerotis Blume ,sed foliis majoribus 26–40 cm longis subtus hispidis,nervulis reticulatis,bracteis conspicue lonioribus,calycibus fissilobis, lobis calycis lineario-lanceolatis 5–6 mm longis differt.A L. megaphyllo H.Zhu foliis subtus hispidis basi subrotundatis, petiolis longioribus, cymis capitatis brevi-pedunculatis, bracteis numerosis 3 cm longis differt. — Typus: Burley et al. 858 (holo L), Kalimantan, S. Kahayan, 150 m alt., in primary lowland forest, 1 May 1988.

Shrub, 1–1.5 m high; branchlets robust, 6–7 mm diam, fistulose, compressed, glabrescent. Leaves: blades obovate-oblong, coriaceous, 26–46 by 10–12 cm, glabrous above, hispid hairs on venation beneath, apex cuspidate to obtuse, base subrounded; midrib depressed above, conspicuously prominent beneath, hispid beneath, nerves depressed above, prominent beneath, 12–15 pairs, ascending at an angle of c. 60°, curved to the margin, hispid beneath, nervules depressed above, prominent beneath, reticulate; petioles c. 1 cm long, hirsute. Stipules triangular-lanceolate, c. 1 cm long, 4–5 mm broad at base. Inflorescences axillary, capitate, very short pedunculate or subsessile; peduncles 1– 2 mm long; bracts numerous, linear, up to 3 cm long, densely hirsute. Flowers covered by bracts, sessile; calyx split into 5 linear-lanceolate lobes near to the base lobes 5 – 6 mm long, 1 mm broad, hirsute external surface and densely hirsute at apex, glabrous internal surface; corolla 12 mm long, subglabrous except the upper part; style filiform, up to 15 mm long; stigma 4–5, filiform. Drupes subglabrous, 6 mm diam, conspicuously 6-ridged, smooth; pyrenes 6, smooth on the abaxial face, ovate-triangular in transverse section.

Distribution — Endemic to Borneo ( Sarawak, Kalimantan).

Habitat & Ecology — In lowland dipterocarp forest. Flowering in May; fruiting in February.

Additional specimens examined. W Kalimantan, W.de Jong 760 (L), A.C. Church et al. 1681; Borneo, unknown coll., L barcode L0310812, L0310813; Borneo, H. Hallier 2016, Teysmann 8005; Sarawak, W.M.A. Brooke 9348.

Note — This species has the biggest leaves and the longest bracts in the genus. It is close to L. rhinocerotis by its similar capitate inflorescence with short peduncles and numerous linear bracts. It differs from the latter by having much larger leaf blades (26–40 cm long) covered with hispid hairs beneath, and with reticulate nervules; bracts up to 3 cm long; calyx split to the base; calyx lobes linear-lanceolate, 5– 6 mm long. It differs from L. megaphyllus by having leaves with subrounded base, hispid beneath; leaf venation more prominent beneath; petioles 1 cm long; inflorescence capitate, very short pedunculate; bracts numerous, linear, up to 3 cm long, densely hirsute.