Hydriastele montana (Becc.) Baker & Loo (2004: 66)

Petoe, Peter, Heatubun, Charlie D. & Baker, William J., 2018, A monograph of Hydriastele (Areceae, Arecaceae) in New Guinea and Australia, Phytotaxa 370 (1), pp. 448-450 : 448-450

11. Hydriastele montana (Becc.) Baker & Loo (2004: 66) . Nengella montana Beccari (1877: 33) . Kentia beccarii Mueller (1880: 163) , nom. superfl. & nom. illeg. Gronophyllum montanum (Becc.) Essig & Young (1985: 134) . Type:— INDONESIA. West Papua Province: Tamrau Mts., Gunon [Gunung] Morait, 1300–1500 m, 0°45’S, 132°30’E, July 1875, Beccari s.n. (holotype FI!, isotype K!)

Figure 24 (line drawing). Figure 25 (photo plate). Figure 23 (map).

Clustering and gregarious understorey palm to 1.5 m tall, very slender, bearing 4–5 leaves per crown, forming suckers by vigorous rhizomatous growth. Stem 5–8 mm in diam. Leaf 25–50 cm long including petiole; sheath 10–15 cm long; petiole 3–8 cm long; leaflets ca. 9–11 per side, regularly arranged, single- or bi-fold, narrowly linear, praemorse or pointed apically, ramenta apparently lacking. Inflorescence 7–9 cm long including 1–1.5 cm peduncle, spicate, protandrous; spike yellowish to green; triads spirally arranged. Staminate flower 9–10 × 1.5–2.5 mm in bud; stamens 6. Pistillate flower 4–4.5 × 3–3.5 mm in bud, with free sepals and free petals with conspicuous, triangular and valvate tips. Fruit ca. 12–19 × 4 mm when ripe (when dry), fusiform, red, with a distinct, dark, sclerotic zone encircling apical stigmatic remains (up to ca. 2 mm in diam.). Seed ca. 12–14 × 3 mm (when dry), elongate to turbinate; endosperm homogenous.

Distribution:— The Tamrau Mountains of the Bird’s Head Peninsula, western New Guinea.

Habitat:— Premontane rainforest on ridges and slopes, 950–1300(–1500) m.

Uses:— None recorded.

Vernacular names:— None recorded.

Conservation status:— Data deficient (DD; Heatubun et al. 2018).

Specimens examined:— INDONESIA. West Papua Province: Kabupaten Tambrauw, Gunon [Gunung] Morait , 1300–1500 m, 0°45’S, 132°30’E, July 1875, Beccari s.n. (FI!, K!); Kabupaten Tambrauw, Bamusbama distr. , road to Fef, 950 m, 0°46’S, 132°16’E, 28 January 2013, Baker et al. 1380 (AAU!, BO!, K!, L!, MAN!); Locality info lacking, recently collected, Iwanggin 132 (MAN, K!) .

Notes:— Hydriastele montana is a slender understorey palm with a gregarious habit, resulting from the production of multiple running rhizomes. It is distinguished by its leaves with 9–11 narrowly linear leaflets on each side of the rachis in combination with a spicate inflorescence and homogeneous endosperm. Hydriastele montana is most similar to H. divaricata and H. flabellata , but the former species has leaves with irregularly to subregularly arranged, divaricate leaflets and ruminate endosperm while the latter displays an entire-bifid leaf lamina or the blade is pinnate with up to six cuneate leaflets on each side of the rachis. Hydriastele montana is described in more detail by Heatubun et al. (2018).

Figures

FIGURE 23. Distribution map of part of the species of the Nengella group of Hydriastele.

FIGURE 24. Hydriastele montana. A. Stem basal portion with running rhizomes and roots. B. Leaf diagram. C. Apical and mid-leaf portion.D. Inflorescences with pistillate flowers. E. Portion of rachilla with pistillate flowers. F. Pistillate flower whole and in longitudinal section. Scale bar: A, C = 4 cm; B = 18 cm; D = 2 cm; E = 7 mm; F = 4 mm.All from Baker et al. 1380. Drawn by Lucy T. Smith.

FIGURE 25. Hydriastele montana. A–B. Habit. C. Infructescence.A, C from Aifat, Bird’s Head Peninsula, western New Guinea; B from Baker et al. 1380. Photos A, C: C.D. Heatubun; B: W.J. Baker.