Hydriastele lurida (Becc.) Baker& Loo(2004:65)

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

13. Hydriastele lurida (Becc.) Baker& Loo(2004:65) . Gronophyllum luridum Beccari(1909:207) .Type:— INDONESIA. Papua Province: Noord-Rivier [Lorentz River], 6 July 1907, Versteeg 1388 (holotype FI!, isotypes BO, K!, L!)

Gronophyllum brassii Burret (1939: 205) . Hydriastele brassii (Burret) Baker & Loo (2004: 63) . Type:— PAPUA NEW GUINEA. Western Province: Palmer R., June 1936, Brass 7093 (holotype B†, isotypes A!, BRI, BO!, L!), synon. nov.

Figure 27 (line drawing). Figure 28 (photo plate). Figure 29 (map).

Solitary, moderately slender subcanopy palm to 25 m tall, bearing 8–12 leaves in crown. Stem (4.5–)6–10(–15) cm in diam. Leaf 1.3–2 m long including petiole; sheath 47–105 cm long, conspicuously fibrous at the sheath mouth; petiole 25–100 cm long; leaflets (21–)27–40 per side, arranged irregularly with one or more groups present, closely spaced and held in different planes, single- or multi-fold, linear to narrowly cuneate, truncately praemorse apically, brittle when dry. Inflorescence 42–70 cm long including 3–6 cm peduncle, branched to 2 orders, protandrous; rachillae (10–)15–27, yellowish; triads spirally arranged. Staminate flower 3–7 × 1–3 mm in bud; stamens 6(–7). Pistillate flower 1–4 × 1–3 mm in bud, with free sepals and free petals with conspicuous, triangular and valvate tips. Fruit 5–7 × 5–7 mm when ripe, globose, red, with a distinct, dark, sclerotic zone encircling apical stigmatic remains (up to ca. 3.5 mm in diam.). Seed 4–5 × 4–5 mm, globose; endosperm ruminate.

Distribution:— Known from various parts of western New Guinea, Gag Island and Biak Island, and from Western Province in Papua New Guinea.

Habitat:— Lowland swamp and heath forest, occasionally in drier habitats or in disturbed roadside vegetation, 5–500 m.

Uses:— Stems used for making harpoons, floors and beds, leaves used for roofing. Shoot apices consumed.

Vernacular names:— Ansan (Soon), Gulbotom (Gebe), Omdar (Biak), Sirata (Sayal).

Conservation status:— Least Concern (LC). This species is widespread (EOO> 258,000 km 2) and the relatively low AOO (36 km 2) is a conservative estimate expected to increase with more records of H. lurida .

Specimens examined:— INDONESIA. Papua Province: Biak Island, Fanjur village, North Supiori Nature Reserve , 50 m, 0°45’S, 135°35’E, 12 June 2001, Maturbongs 679 (AAU, BO, CANB, K!, MAN); Same locality as preceding, 0°45’S, 135°35’E, 13 June 2001, Maturbongs 685b (AAU, BO, K!, MAN); Biak Island , near Soon village , 134 m, 1°7’S, 136°13’E, 23 July 2009, Baker et al. 1339 (AAU, BO, K!, MAN); Noord-Rivier [Lorentz River], 4°40’S, 138°43’E, 6 July 1907, Versteeg 1388 (FI!, K!, L!); Timika, between Timika and port, peat lens (plot 22), Loc 20, 5 m, 4°47’S, 136°51’E, 16 February 1998, Dransfield 7682 (BH, BO, K!, L, MAN); Timika, Km 58 on road to Tembagapura, Loc 4, 185 m, 4°22’S, 136°56’E, 8 February 1998, Baker et al. 823 (AAU, BH, BO, K!, L, MAN); Dalman, 45 km inward of Nabire, 500 m, 2 March 1940, Kanehira 12126 (A!) ; West Papua Province: Sorong Selatan, Sayal, Maampow , 10 m, 1°28’S, 131°53’E, 21 February 2003, Heatubun 422 (MAN, K!, BO); Kabupaten Raja Ampat, Gag Island , Swamp forest behind Mining Base Camp, 10 m, 0°27’S, 129°54’E, 2 August 2006, Heatubun 765 (BO, K!, MAN); Distr. Manokwari, Subdistr. Bintuni, between Saengga & Tanah Merah villages, 9 m, 2°27’S, 133°7’E, 13 February 2002, Maturbongs 709 (BO, K!, LAE, MAN) ; PAPUA NEW GUINEA. Western Province: Palmer River below junction with Black River 2 m, 100 m, 5°47’S, 141°42’E, June 1936, Brass 7093 (A, BO!, BRI, L!) .

Notes:— Hydriastele lurida is a moderately slender subcanopy palm distinguished by its fibrous leaf sheaths, leaves with 27–40 irregularly arranged leaflets on each side of the rachis (rarely as few as 21 leaflets per side), and inflorescences branched to two orders with spirally arranged triads. Hydriastele lurida may superficially resemble H. wendlandiana in habit, although that species belongs to the Wendlandiana group, does not have conspicuously fibrous leaf sheaths and generally has leaves with fewer leaflets. Hydriastele lurida is unlikely to be confused with other species in New Guinea.

Hydriastele lurida most closely resembles H. microcarpa ( Scheffer 1876: 153) Baker & Loo (2004: 65) and H. oxypetala ( Burret 1937a: 474) Baker & Loo (2004: 66) , which both occur in the Moluccas. Our preliminary work indicates that H. lurida can be distinguished from those two species based on its more closely spaced leaflets, having 24 to 39 leaflets per side per meter rachis as opposed to only 16 to 21 leaflets per side per meter rachis in H. microcarpa and H. oxypetala .

Here we place H. brassii in synonymy under H. lurida , having thoroughly examined the type material. In his protologue of H. brassii, Burret makes comparison to the related H. microcarpa , but does not mention H. lurida .

SIPHOKENTIA GROUP

Moderate palms, inflorescences protandrous and branched to 1 or 2 orders, triads largely decussately arranged, pistillate sepals and petals uniquely fused in a cup. The Moluccas and the Biak Islands.

Figures

FIGURE 27. Hydriastele lurida. A. Leaf apex. B. Mid-leaf portion.C. Petiole base. D. Infructescence.E. Portion of rachilla with pistillate flowers. F. Staminate flower whole and in longitudinal section. G. Pistillate flower whole and in longitudinal section. H. Portion of rachilla with fruit. I. Fruit in longitudinal section. Scale bar: A–B = 8 cm; C = 3 cm; D = 6 cm; E, H = 1 cm; F–G = 3 mm; I = 5 mm. A–D, H–I from Baker et al. 823; E–G from Dransfield 7682. Drawn by Lucy T. Smith.

FIGURE 28. Hydriastele lurida. A–B. Crown. C. Sheath mouth. D. Infructescence. A from Biak Island; B–D from Baker et al. 1339. All photos: W.J. Baker.

FIGURE 29. Distribution map of the Microcarpa group of Hydriastele in New Guinea and adjacent islands.