Iguanura bruneiensis Henderson, 2025

Henderson, Andrew, 2025, A revision of Iguanura (Arecaceae, Arecoideae, Areceae), Phytotaxa 690 (2), pp. 135-188 : 152-154

6. Iguanura bruneiensis Henderson sp. nov. Type:— BRUNEI. Tutong District, track from Panchong to Benutang, 4°37’S 114°42’W, 5–10 m, 21 October 1989, L. Forman & J. Blewett 1001 (holotype BRUN n.v., isotype K-001260713!). Plate 3 .

Stems length not recorded, 0.9 cm diameter, branching not recorded. Leaf sheaths 12.0 cm long, tubular, mostly closed opposite the petiole, cleanly falling, covered with a thin layer of indumentum; ocreas well-developed, separating early into fibers and disintegrating; petioles 20.0 cm long; rachises 30.5 cm long; leaf blades divided, not rounded at the apex, with a deep split; leaf veins parallel; adaxial leaf veins prominent, rectangular in cross-section; pinnae 3 per side of rachis; middle pinna 15.7 cm long, 5.2 cm wide. Inflorescences branched to 1 order; prophylls and peduncular bracts inserted some distance apart, more or less persistent; peduncles length not recorded, not wooly tomentose; rachises 1.0 cm long; rachillae 4, 7.0 cm long, 1.4 mm diameter, widely diverging from the rachis, proximal part of rachillae not with distantly spaced triads, glabrous or sparsely tomentose, not filiform with triads sunken in shallow, more or less closely spaced pits; 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 not recorded; fruits 9.4 mm long, 6.6 mm diameter, ellipsoid, ridged, the surfaces drying pebbled, white; endocarp polygonal in cross-section; endosperm homogeneous.

Distribution and habitat:— Brunei in swampy, secondary forest at 7 m elevation ( Fig. 8 ).

Taxonomic notes:— Iguanura bruneiensis is recognized as a phylogenetic species—see notes under I. borneensis . It is characterized by its tubular, mostly closed, cleanly falling sheaths, non-filiform rachillae, proximal part of rachillae not with distantly spaced triads, and ridged fruits with the surfaces drying pebbled.

Figures

PLATE 3. Isotype of Iguanura bruneiensis (image created and provided by the Royal Botanic Gardens, Kew).

FIGURE 8. Distribution of Iguanura brevipes, I. bruneiensis, I. chaiana, and I. curvata.