Iguanura montana Henderson, 2025

Henderson, Andrew, 2025, A revision of Iguanura (Arecaceae, Arecoideae, Areceae), Phytotaxa 690 (2), pp. 135-188 : 169-171

21. Iguanura montana Henderson , sp. nov. Type:— MALAYSIA. Sarawak, 1 st /2 nd Division border, G. Buri, near summit, 700 m, 22 nd May 1981, J. Dransfield 6109 (holotype SAR!, isotypes BH!, K-001260775!, L-0616433!). Plate 8.

Stems 0.2 m long, 1.3(1.2–1.5) cm diameter, solitary. Leaf sheaths 8.8(8.0–9.5) cm long, open and more or less persistent, not cleanly falling, initially covered with dense, woolly indumentum; ocreas well-developed, separating early into fibers and disintegrating; petioles 24.0(17.0–31.0) cm long; rachises 33.3(26.5–40.0) cm long; leaf blades divided, not rounded at the apex, with a deep split; leaf veins parallel; adaxial leaf veins prominent, rectangular

PLATE 8. Isotype of Iguanura montana .

in cross-section; pinnae 7(2–14) per side of rachis; middle pinna 23.8(20.3–30.0) cm long, 3.5(1.8–5.5) cm wide. Inflorescences branched to 1 or 2 orders; prophylls and peduncular bracts inserted some distance apart, more or less persistent; peduncles length not recorded, densely reddish-brown, wooly tomentose; rachises 5.0(3.0–7.0) cm long; rachillae 8(5–13), 10.0(8.0–12.0) cm long, 0.9(0.8–1.0) mm diameter, widely diverging from the rachis, proximal part of rachillae not with distantly spaced triads, densely tomentose, filiform with superficial, distantly spaced triads; rachilla bracts not elongate; distal triad bracteoles well-developed; distal part of flower pits glabrous; staminate flowers 2.0– 2.5 mm long with blunt apices; anther margins undulate; fruits 12.9(11.7–13.5) mm long, 6.6(5.3–7.2) mm diameter, oblong, apiculate, ridged, the surfaces drying smooth, pink or reddish-pink; endocarp semicircular in cross-section; endosperm homogeneous.

Distribution and habitat:— Malaysia ( Sarawak) in hill Dipterocarp forest or mixed Dipterocarp forest at 518(181–700) m elevation (Fig. 12).

Taxonomic notes:— Iguanura montana is recognized as a phylogenetic species — see notes under I. palmuncula . It is characterized by its sheaths covered with dense, woolly indumentum, filiform rachillae, and oblong, apiculate fruits.

Subspecific variation:—There are two specimens (J. Dransfield 6109, P. Chai S.36754) from Gunung Buri at 530–700 m elevation. They appear to be short-stemmed or acaulescent palms and have small leaves with 2–4 pinnae per side of the rachis. These are isolated geographically from the two other specimens (L. Julaihi S.83536, S. Nilla S.105351A) from the hills south and east of Gunung Buri at 181–660 m elevation. These also appear to be short-stemmed palms but have much larger leaves with numerous pinnae per side of the rachis, 14 in L. Julaihi S.83536.