Iguanura borneensis Scheffer (1876: 161)

Henderson, Andrew, 2025, A revision of Iguanura (Arecaceae, Arecoideae, Areceae), Phytotaxa 690 (2), pp. 135-188 : 151

4. Iguanura borneensis Scheffer (1876: 161) . Type:— INDONESIA. Borneo, Landak, no date, J. Teysmann s.n. (holotype BO n.v., BO image!, isotype FI-014180!).

Stems length, diameter, and branching not recorded. Leaf sheaths 10.0 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 12.5 cm long; rachises 30.0 cm long; leaf blades undivided, not rounded at the apex, with a deep split; leaf veins parallel; adaxial leaf veins prominent, rectangular in cross-section; pinnae 1 per side of rachis. Inflorescences branched to1 order; prophylls and peduncular bracts inserted some distance apart, more or less persistent; peduncles 12.0 cm long, not wooly tomentose; rachises 1.0 cm long; rachillae 4, 8.0 cm long, 2.3 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 elongate, acuminate, densely tomentose at apex; distal triad bracteoles well-developed; distal part of flower pits densely tomentose; staminate flowers 4.0–5.0 mm long with pointed apices; anther margins not recorded; fruits not recorded.

Distribution and habitat:— Indonesia (West Kalimantan), habitat and elevation not recorded ( Fig. 7 ).

Taxonomic notes:— Preliminary species Iguanura borneensis was polymorphic for six variables. Three of these (leaf division, rachillae tomentum, pit tomentum) were treated as traits, and the other three (leaf venation, rachilla bracts, staminate flowers) were used to split preliminary species I. borneensis into three phylogenetic species, I. borneensis , I. australis , and I. bruneiensis . Iguanura borneensis is characterized by its parallel leaf venation and rachilla bracts that are elongate, acuminate, and densely tomentose at the apex.

Kiew (1979) determined one specimen ( Clemens 20708) from Sarawak as I. borneensis . It is here determined as I. sarawakensis .

Figures

FIGURE 7. Distribution of Iguanura australis, I. beccarii, I. bicornis, and I. borneensis.