Hydriastele kasesa (Lauterb.) Burret (1937b: 484)

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

2. Hydriastele kasesa (Lauterb.) Burret (1937b: 484) . Ptychosperma kasesa Lauterbach (1911: 357) . Adelonenga kasesa (Lauterb.) Beccari (1914: 26) . Type:— PAPUA NEW GUINEA. New Ireland Province: Namatanai, Peekel 109 (holotype B†, isotype FI!)

Figure 5 (line drawing). Figure 4 (map).

Solitary or clustering palm forming clumps of as many as 15 stems, slender, to 6 m tall, bearing 6–8 leaves per crown. Stem 1.5–3.8 cm in diam. Leaf 70–150 cm long including petiole; sheath 15–30 cm long; petiole 15–40 cm; leaflets 6–13 per side, arranged irregularly, with a group of closely spaced leaflets in different planes in the middle of rachis, ± cuneate, truncately praemorse apically, ramenta seemingly lacking. Inflorescence 17–30 cm long including 2–4 cm peduncle, branched to 1 or 2 orders, protogynous; primary branches 5–10, to 23.5 cm long, bearing up to 3 rachillae each; triads opposite and decussate. Staminate flower 8 × 3–4 mm in bud (when dry); stamens 6. Pistillate flower ca. 2.5 × 2.5 mm in bud (when dry), with free sepals and free, ± rounded, low petals. Fruit ca. 12 × 9 mm when ripe, ovoid to subglobose, red, with inconspicuous stigmatic apical remains lacking encircling dark sclerotic zone. Seed ca. 6.7 × 5.4 mm (when dry), ovoid; endosperm ruminate.

Distribution:— New Britain and New Ireland in the Bismarck Archipelago.

Habitat:— Lowland tropical primary rainforest, occasionally on swampy ground or near stream banks, and premontane mixed forest on slopes and ridges, 0–800 m.

Uses:— None recorded.

Vernacular names:— None recorded.

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

Specimens examined:— PAPUA NEW GUINEA. East New Britain Province: Rabaul Subdistr., Matanakunei , 0 m, 4°52’S, 151°43’E, 29 March 1968, Ridsdale 38004 (BH, BRI, CANB, L!) ; New Ireland Province: Namatanai, Peekel 109 (B†, FI!); Namatanai Subdistr., Hans Meyer Range , Danfu River Valley about 8 km west and upstream of the Danfu bridge nr. Manga , 800 m, 4°11’S, 152°57’E, 14 February 1970, Sands 866 (K!, L, LAE); inland from Lossuk to Bagaterra, 0 m, 2°45’S, 151°4’E, 3 February 1967, Coode 29729 (LAE!); near the junction of the Niagara and Weitin River , 240 m, 4°30’S, 152°56’E, 19 January 1994, Takeuchi 9902 (A!); near the junction of the Niagara and Weitin River , 240 m, 4°30’S, 152°56’E, January 1994, Takeuchi 9994 (A!); Subdistr. Lamet, West New Hanover , 2 km E of Metemulai village, 50 m, 2°30’S, 150°2’E, 7 October 1974, Croft 65490 (BH, L!, LAE); Namatanai Subprovince, Lihir Island , Mt. Tementa above Palie Mission, 600 m, 3°12’S, 152°36’E, 7 November 1984, Gideon 57205 (L!, LAE, USP) ; West New Britain Province: Eiliak, 15 m, 5°45’S, 149°5’E, 7 May 1958, White 10070 (BRI, CANB!, L!, LAE); Gasmata Subdistr., Gasmata patrol post, 40 m, 6°15’S, 150°19’E, 30 May 1987, Kerenga 62320 (LAE!); Gasmata Subdistr., 6 miles east of Fullerborn Harbour , 300 m, 6°6’S, 150°38’E, 8 May 1973, Isles 34405 (A, BRI, K!, L!, LAE, CANB!); Talasea Subdistr., Koimumu-Lavege Road, 5°36’S, 150°25’E, 17 April 1959, White 10889 (A, BRI, K!, LAE); Talasea Subdistr., Kimbe, 0 m, 5°33’S, 150°9’E, 26 April 1972, Essig 55214 (LAE!); Mt. Klangal , 25 miles NNE of Gasmata, 800 m, 6°00’S, 150°30’E, 15 May 1973, Croft 15567 (BH, L!, LAE) .

Notes:— Hydriastele kasesa is a slender understorey palm distinguished by its leaves with 6–13 irregularly arranged leaflets on each side of the rachis, leaf sheaths up to 30 cm long, and inflorescences bearing 5–10 primary branches. Hydriastele kasesa is most similar to H. wendlandiana to which it is no doubt closely related, but H. wendlandiana is usually taller and less slender, has leaves with 12–40 leaflets on each side of the rachis (rarely 12–13 leaflets per side), leaf sheaths longer than 40 cm, and inflorescences with 8–15 primary branches.

Hydriastele kasesa 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 5. Hydriastele kasesa. A. Leaf apex. B. Mid-leaf portion. C. Leaf base. D. Leaf sheaths and inflorescences. E. Infructescence. F. Staminate flower whole and in longitudinal section. G. Pistillate flower whole, two views, and in longitudinal section. H. Portion of rachilla with fruit. I. Fruit in longitudinal section. Scale bar: A–C = 8 cm; D = 6 cm; E = 4 cm; F = 5 mm; G = 2.2 mm; H = 1 cm; I = 7 mm. All from Takeuchi 9902. Drawn by Lucy T. Smith.