Hydriastele variabilis (Becc.) Burret (1937b: 483)

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

3. Hydriastele variabilis (Becc.) Burret (1937b: 483) . Nenga variabilis Beccari (1877: 26) . Adelonenga variabilis (Becc.) Beccari (1885: 82) . Type:— INDONESIA. West Papua Province: Ramoi, 1872, Beccari PP426 (holotype FI!, isotype K!)

Nenga variabilis var. sphaerocarpa Beccari (1877: 27) . Hydriastele variabilis var. sphaerocarpa (Becc.) Burret (1937: 483) . Type:— INDONESIA. West Papua Province: Amberbakin, 1872, Beccari s.n. (holotype FI!, isotype K!).

Figure 6 (line drawing). Figure 7 (photo plate). Figure 4 (map).

Clustering, slender palm to 8 m tall, bearing 4–7 leaves per crown. Stem 2–4 cm in diam. Leaf 95–140 cm long including petiole; sheath 27–45 cm long; petiole 9–30 cm long; leaflets 11–23 per side, arranged regularly to subregularly, linear; basal leaflets single-fold, pointed or obliquely praemorse apically; terminal leaflets comprising 4–11 folds, truncately praemorse apically; Inflorescence 10–25 cm long including 2–2.5 cm peduncle, branched to 1 or 2 orders, protogynous; primary branches 6–11, to 22 cm long, bearing up to 1 rachilla each; triads opposite and decussate. Staminate flower not seen. Pistillate flower 2–2.5 × 2–3 mm in bud (when dry) with free sepals and free, ± rounded, low petals. Fruit 10–12 × 6.3–7.8 mm when ripe, ellipsoid to ovoid with ends ± tapering when dry, red, with inconspicuous stigmatic apical remains lacking encircling dark sclerotic zone. Seed 7–8.2 × 5–6 mm, ovoid; endosperm deeply ruminate.

Distribution:— Northern Bird’s Head Peninsula and the adjacent Bomberai Peninsula in West Papua Province, western New Guinea.

Habitat:— Primary or secondary lowland tropical rainforest or premontane primary rainforest on soils with a varying composition of clay, sand, humus and fibrous roots, 0–1200 m.

Uses:— None recorded.

Vernacular names:— Sagarofa (Sumuri), Pinang Oetan (Malay).

Conservation status:— Least Concern (LC; Petoe et al. 2018).

Specimens examined:— INDONESIA. West Papua Province: Ramoi, 1872, Beccari PP 426 (FI!, K!); Amberbakin, 1872, Beccari s.n. (FI!, K!); Manokwari Distr., Bintuni Subdistr., beside trail between Saengga & Tanah Merah Villages, 20 m, 2°27’S, 133°7’E, 13 February 2002, Maturbongs 712 (BO, K!, LAE, MAN); Manokwari Distr., Bintuni Subdistr., near Saengga Village , 20 m, 2°27’S, 133°6’E, 13 February 2002, Sambas 17 (BO, K!, LAE, MAN); Manokwari, around a construction main road of Manokwari-Sorong, between Wariori River and Waramoi River, 400 m, 0°48’S, 133°38’E, 26 April 1994, Mogea 6305 (AAU, BO, BRI, K!, L, MAN, NY); Manokwari, Kebar, Kebar Valley , trail from Andjai to G. Nettoti near base camp ‘N’ on ridge at 1000m, 1240 m, 0°46’S, 133°3’E, 3 May 1995, Davis 726 (BO, BRI, K!, MAN, NY); Sorong , Klasaman, Km27, Intimpura Camp, 120 m, 0°58’S, 131°28’E, 20 September 1995, Maturbongs 292 (K!); Sorong , Klasaman, KM 14, 40 m, 0°55’S, 131°22’E, 15 September 1995, Wally 464 (K!); Sorong , Roefei river N of Sorong, ca. 2 miles from the sea on northern bank, 90 m, 0°51’S, 131°15’E, 24 March 1954, van Royen 3155 (CANB!, L!); Sorong Distr. , Klasaman, Klabainem, 10 m, 0°55’S, 131°21’E, 29 February 2002, Heatubun 375 (K!, MAN); Tamrau Mountains , Sorong-Manokwari road, beyond Bamus Buma, towards Fef and Manokwari, 950 m, 0°45’S, 132°17’E, 28 January 2013, Gardiner 424 (BO, K!, L, MAN); Tambrouw Regency, Fef Distr. ; Pass above Fef, 700 m, 0°49’S, 132°27’E, 24 January 2013, Baker et al. 1369 (BO, K!, L, MAN); Sorong Regency, Klaso Distr. ; Kalalin, near Megame, 100 m, 0°46’S, 131°49’E, 31 January 2013, Baker et al. 1390 (BO, K!, L, MAN); Locality info lacking, recently collected, Iwanggin 134 (MAN, K!) .

Notes:— Hydriastele variabilis is a slender understorey to midstorey palm bearing leaves with regularly to subregularly arranged, linear leaflets. The species is distinguished by its leaves with a well-defined petiole, basal leaflets with pointed to obliquely praemorse tips, and a terminal leaflet pair comprising 4–11 folds. The infructescence is rather distinctive in being branched to one or two orders, and bearing fruits that become somewhat fusiform upon drying. Hydriastele variabilis is superficially similar to H. kasesa in the slender habit but that species has irregularly arranged leaflets. While H. apetiolata and H. rheophytica both are regularly pinnate, the former species is less slender with apetiolate adult leaves, while the latter is a rheophyte with pliable stems and terminal leaflets comprising 2 or 3 folds. Rarely, the leaflets in H. wendlandiana can be regularly arranged prompting comparison with H. variabilis but H. wendlandiana has basal leaflets with truncately praemorse tips.

Hydriastele variabilis is described in more detail by Petoe et al. (2018).

Figures

FIGURE 4. Distribution map of the species of the Wendlandiana group of Hydriastele.

FIGURE 6. Hydriastele variabilis. A. Habit. B. Leaf apex. C. Mid-leaf portion. D. Inflorescences with pistillate flowers; E Portion of rachilla with pistillate flowers. F. Pistillate flower whole and in longitudinal section. G. Portion of rachilla with fruit. H. Fruit in longitudinal and transverse section. Scale bar: A = 40 cm; B–C = 4; D = 6 cm; E = 1 cm; F = 3 mm; G = 1.5 cm; H = 7 mm. A, D–F from Gardiner 424; B–C, G–H from Baker et al. 1369. Drawn by Lucy T. Smith.

FIGURE 7. Hydriastele variabilis.A–B. Habit. C. Inflorescences with pistillate flowers. D. Infructescence with immature fruit.A, C from Gardiner 424; B, D from Aifat, Bird’s Head Peninsula, western New Guinea. Photos A, C: W.J. Baker; B, D: C.D. Heatubun.