Hydriastele flabellata (Becc.) Baker & Loo (2004: 64)

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

10. Hydriastele flabellata (Becc.) Baker & Loo (2004: 64) . Nengella flabellata Beccari (1877: 34) . Gronophyllum flabellatum (Becc.) Essig & Young (1985: 134) . Type:— INDONESIA. West Papua Province: Sorong, Ramoi, 0°57’S, 131°20’E, 1872, Beccari 427 (holotype FI!)

Nengella calophylla var. montana Beccari (1914: 27) . Nengella pleurocarpa Burret (1936c: 314) . Gronophyllum pleurocarpum (Burret) Essig & Young (1985: 136) . Hydriastele pleurocarpa (Burret) Baker & Loo (2004: 67) . Type:— PAPUA NEW GUINEA. Madang Province: 12 July 1907, Schlechter 16251 (holotype B†, isotype FI!).

Nengella calophylla var. rhopalocarpa Beccari (1914: 28) . Nengella rhopalocarpa (Becc.) Burret (1936c: 314) . Gronophyllum rhopalocarpum (Becc.) Essig & Young (1985: 136) . Hydriastele rhopalocarpa (Becc.) Baker & Loo (2004: 67) . Type:— PAPUA NEW GUINEA. Morobe Province: Waria River, 7°58’S, 147°28’E, 13 March 1908, Schlechter 17466 (holotype B†, isotypes FI!, K!).

Nengella gracilis Burret (1939: 206) . Gronophyllum gracile (Burret) Essig & Young (1985: 134) . Hydriastele gracilis (Burret) Baker & Loo (2004: 65) . Type:— PAPUA NEW GUINEA. Western Province: Palmer River, 2 min. below junction Black River, 100 m, 5°47’S, 141°42E, June 1936, Brass 7083 (holotype A!).

Gronophyllum cariosum Dowe & Ferrero (2000a: 161) . Hydriastele cariosa (Dowe & M.D.Ferrero) Baker & Loo (2004: 63) . Type:— PAPUA NEW GUINEA. Sandaun Province: Bewani Mts., Nuli River, 120 m, 3°58’S, 141°10’E, 12 February 1998, Dowe 514 (holotype BRI).

Figure 21 (line drawing). Figure 22 (photo plate). Figure 23 (map).

Clustering, very slender understorey palm to 4 m tall, bearing 4–8 leaves per crown. Stem 1–2 cm in diam. Leaf 35–90 cm long including petiole; sheath 8–23 cm long; petiole 10–30 cm; lamina 20–65 cm long, entire-bifid, bijugate or more finely dissected with up to 6 leaflets per side, ramenta apparently lacking; leaflets (when present) regularly or irregularly arranged, single- or multi-fold, cuneate, praemorse apically. Inflorescence 8–15 cm long including 1–3 cm peduncle, spicate or branched to 1 order, protandrous; rachillae 1–2 (up to 3 rachillae known from cultivation), green to yellow; triads spirally arranged. Staminate flower 8–10 × 2–3 mm in bud, cream to violet; stamens 6. Pistillate flower 3–5 × 2–3.5 mm in bud, cream to light green or lavender, with free sepals and free petals with conspicuous, triangular and valvate tips. Fruit 12–15 × 5–8 mm when ripe, ellipsoid to fusiform, red, with a distinct, dark, sclerotic zone encircling apical stigmatic remains (up to ca. 1.5 mm in diam.). Seed 10–12 × 4–7 mm, ellipsoid; endosperm homogeneous.

Distribution:— Scattered across New Guinea from the Bird’s Head Peninsula in western New Guinea to Central Province in Papua New Guinea.

Habitat:— Primary rainforest, mainly lowland, on slopes, ridges and riverbanks. On waterlogged alluvium, limestone karst and volcanic soils, 0–700 m.

Uses:— Leaves used as food wrapping, stems used for making arrow shafts and fish spear handles.

Vernacular names:— Mplemponik (Sayal), Filiawoi Yamu (Bewani).

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

Specimens examined:— INDONESIA. West Papua Province: Sorong, Ramoi, 0°57’S, 131°20’E, 1872, Beccari 427 (FI!); Sorong Selatan Regency , Sayal , Maampow Forest , 10 m, 1°28’S, 131°53’E, 21 February 2013, Heatubun 406 (K (spirit)!, MAN!); same locality as preceding, 10 m, 1°28’S, 131°53’E, 21 February 2013, Heatubun 426 (K (spirit)!, MAN!); Kaimana Regency, Teluk Etna, Waribun, Km-27 road to Kaltim Hutama, 100 m, 31 January 2001, Heatubun 329 (K!, MAN!); Surroundings of Ayawasi , 450 m, 1°5’S, 132°17’E, 16 January 1996, Polak 1000 (BO, L!) ; Papua Province: Maribu village, Cyclops Mts. Nature Reserve, 850 m, 2°29’S, 140°23’E, 21 September 1998, Maturbongs 576 (BO, K!, MAN,); Mimika Regency, Timika, Kali Kopi, 95 m, 4°26’S, 136°57’E, 24 February 1998, Baker et al. 879 (BO!, K!, MAN!); Kuala Kencana, 50 m, 4°25’S, 136°51’E, 19 February 1998, Witono 23 (BH, BO!, K!, MAN!); Jayapura, Cyclops Mts. , path to Ormu, 700 m, 2°26’S, 140°37’E, 18 August 1998, Heatubun 285 (BO, FTG, K!, L, MAN) . PAPUA NEW GUINEA. Central Province: Aroa R., 8°55’S, 147°0’E, 29 July 1898, Armit s.n. (MEL!) ; Morobe Province: Morobe Subprovince, Mayama village, 100 m, 7°35’S, 147°10’E, 17 June 1981, Katik LAE 74935 (BRI, L!, LAE, NSW, USF); Kamiali Wildlife Management Area , ridge to Blue Mt, near starting point of the Nembebah PABITRA plot, 650 m, 7°17’S, 147°5’E, 28 February 2005, Takeuchi 18982 (K!, LAE); Waria R., 7°58’S, 147°28’E, 13 March 1908, Schlechter 17466 (B†, FI!, K!) ; Madang Province: 12 July 1907, Schlechter 16251 (B†, FI!) ; Sandaun Province: Roundhouse village, 200–250 m, 3°2’S, 141°7’E, 27 November 1996, Barfod 413 (AAU!, LAE); Bewani, 0 m, 3°1’S, 141°8’E, 19 March 2000, Barfod 499 (AAU!, K!, LAE); Lumi Subdistr., Karataiem, off road between Lumi Govt. Station and Karataiem Catholic Mission, 3°27’S, 142°1’E, January 1974, Frodin s.n. (K!, UPNG); Telefomin Subdistr., Prospect Creek near Frieda R., 500 m, 4°42’S, 141°48’E, 23 June 1969, Henty NGF 42555 (BH, LAE!); Amanab Subdistr., Imonda, along road to Bapi R., 300 m, 3°20’S, 141°10’E, 25 November 1971, Essig LAE 55094 (BH, CANB!, LAE!) ; Southern Highlands Province: Kutubu patrol area, Waro, 500–600 m, 3 August 1991, Takeuchi 7284 (A!, LAE); same locality as preceding, 500–600 m, 3 August 1991, Takeuchi 7312 (A!, LAE); Kantobo, 470 m, 6°44’S, 143°35’E, 9 February 1996, Baker et al. 643 (K!, LAE!); Mt. Bosavi , Wasaso, Bona village , 700 m, 6°26’S, 142°47’E, 2 February 1996, Baker et al. 611 (BH, FTG, K!, LAE); Mt. Bosavi , northern side, 900 m, 6°26’S, 142°50’E, 26 October 1973, Jacobs 9470 (L!, LAE) ; Western Province: Palmer R., 2 min. below junction Black R., 100 m, 5°47’S, 141°42’E, June 1936, Brass 7083 (A!); Same locality as preceding, 100 m, 5°47’S, 141°42’E, June 1936, Brass 7368 (A!). CULTIVATED . UNITED STATES. Hawaiian Islands : Hawai’i, Floribunda Palms, November 2017, Baker et al. 1448 (K!) .

Notes:— Hydriastele flabellata is an understorey palm with a distinctive, highly variable leaf morphology ranging from entire-bifid to pinnate with up to six cuneate leaflets on each side of the rachis. The species is further distinguished by its inflorescences, which are 8–15 cm long and consist of one (spicate) or two rachillae (up to three rachillae is known from cultivation [Baker 1448]), and homogeneous endosperm. Hydriastele flabellata might be confused with H. montana , which is similar in inflorescence morphology but has leaves with 9–11 narrowly linear leaflets on each side of the rachis, or with H. pinangoides , which can have similar looking foliage but is usually taller and displays 18–30 cm long inflorescences with 2–6 rachillae and ruminate endosperm.

Heatubun et al. (2018) discuss the morphology and delimitation of H. flabellata in more detail.

Figures

FIGURE 21. Hydriastele flabellata. A. Habit. B. Portion of crown. C, D, E, F. Leaf diagrams. G. Prophyll. H. Inflorescence with triads. I. Portion of rachilla with triads. J. Staminate flower in longitudinal section. K. Pistillate flower in longitudinal section. L. Fruit whole, in longitudinal section, and in transverse section. Scale bar: A = 20 cm; B = 6 cm; C–F = 18 cm; G–H = 2 cm; I = 5 mm; J = 4 mm; K = 3 mm; L = 7 mm. A–C, G–K from Baker et al. 879; D from Schlechter 17466; E–F from Baker et al. 643; L from Heatubun 406. Drawn by Lucy T. Smith.

FIGURE 22. Hydriastele flabellata. A–B. Habit. C. Inflorescence with triads. D. Infructescences. A, C from Baker et al. 879; B from Baker et al. 1448 (cultivated specimen); D from Timika, western New Guinea.All photos: W.J. Baker.

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