Iguanura lunata Henderson, 2025

Henderson, Andrew, 2025, A revision of Iguanura (Arecaceae, Arecoideae, Areceae), Phytotaxa 690 (2), pp. 135-188 : 163

14. Iguanura lunata Henderson , sp. nov. Type:— MALAYSIA. Sarawak, Ulu Sg. Melinau, Kapit, 7 th Division, 150 m, 4 May 1976, Paul Chai et al. S.37566 (holotype SAR!). Plate 6.

Stems length, diameter, and branching not recorded. Leaf sheaths 13.7 cm long, open and more or less persistent, not cleanly falling, initially covered with dense, woolly indumentum; ocreas not recorded; petioles 48.5 cm long; rachises 46.0 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 5 per side of rachis; middle pinna 26.0 cm long, 5.8 cm wide. Inflorescences branched to 1 order; prophylls and peduncular bracts inserted some distance apart, more or less persistent; peduncles 40.0 cm long, not wooly tomentose; rachises 15.0 cm long; rachillae 20, 17.0 cm long, 0.9 mm diameter, widely diverging from the rachis, proximal part of rachillae not with distantly spaced triads, densely 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 14.6 mm long, 6.9 mm diameter, narrowly ovoid, curved, ridged, the surfaces drying pebbled, pinkish-red; endocarp polygonal in cross-section; endosperm not recorded.

Distribution and habitat:— Malaysia ( Sarawak) in periodically flooded, semi-riverine forest at 150 m elevation ( Fig. 9 ).

Taxonomic notes:— Iguanura lunata is recognized as a phylogenetic species—see notes under I. curvata . It is characterized by its narrowly ovoid, curved, ridged fruits with the surfaces drying pebbled. The type specimen (P. Chai 37566) was cited by Kiew (1979) as I. curvata . However, it differs from that species by its pebbled fruit surfaces and polygonal cross-section of the endocarp. The rachillae are densely tomentose.

Figures

FIGURE 9. Distribution of Iguanura elegans, I. exilis, I. grandis, and I. lunata.