Hydriastele splendida Heatubun, Petoe & W.J. Baker (2018: 18)

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

8. Hydriastele splendida Heatubun, Petoe & W.J. Baker (2018: 18) . Type:— INDONESIA. Papua Province: Mimika Regency (Previously Fakfak Regency), Timika, PT. Freeport Indonesia Area of Work , Km 63 road to Tembagapura , 435 m, 4°21’S, 136°58’E, 7 February 1998, Baker et al. 820 (holotype K!, isotypes AAU!, BH!, BO!, L!, MAN!)

Figure 17 (line drawing). Figure 18 (photo plate). Figure 14 (map).

Solitary or clustering, slender understorey palm to 4 m tall, bearing ca. 4–5 leaves per crown. Stem 1.5–2 cm in diam. Leaf ca. 100 cm long including petiole; sheath ca. 30 cm long; petiole ca. 20 cm long; lamina ca. 80 × 40 cm, entire-bifid, obovate, distal half of margin rounded and praemorse. Inflorescence ca. 18 cm long including ca. 2 cm peduncle, branched to 1 order, protandrous; rachillae 3–4 per inflorescence (as many as 6 known from cultivation), scarlet; triads spirally arranged. Staminate flower not seen. Pistillate flower ca. 4–5 × 3 mm post-anthesis (when dry), crimson, with free sepals and free petals with conspicuous, triangular tips. Fruit ca. 1 cm long when ripe, cylindrical, pink, with a distinct, dark, sclerotic zone encircling apical stigmatic remains (up to ca. 2 mm in diam. when dry). Seed ca. 7 × 1.5 mm (when dry), turbinate; endosperm ruminate.

Distribution:— Known only from the lower slopes of the Mt. Jaya region ( Dransfield et al. 2000) in Papua Province, western New Guinea.

Habitat:— Heath forest on outwashed sands and gravels on steep and mossy slopes with many fallen trees ( Dransfield et al. 2000), 435 m.

Uses:— None recorded.

Vernacular names:— None recorded.

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

Specimens examined:— INDONESIA. Papua Province: Mimika Regency (Previously Fakfak Regency), Timika, PT. Freeport Indonesia Area of Work, Km 63 road to Tembagapura , 435 m, 4°21’S, 136°58’E, 7 February 1998, Baker et al. 820 (AAU!, BH!, BO!, K!, L!, MAN!). CULTIVATED . UNITED STATES. Hawaiian Islands: Hawai’i, Floribunda Palms , November 2017, Baker et al. 1443 (K!) .

Notes:— Hydriastele splendida is a slender understorey palm, immediately recognisable on account of its entire-bifid leaves in combination with inflorescences comprising 3–4 rachillae and ruminate endosperm. The species is similar to H. pinangoides in habit and reproductive morphology, but is easily distinguished from this by its entire leaves. Hydriastele splendida is more readily confused with entire-leaved forms of H. flabellata , but H. flabellata differs in its inflorescences with one (spicate) or two rachillae (three rachillae known from cultivation) and homogeneous endosperm.

Hydriastele splendida appears to be already well established in cultivation, often erroneously named H. flabellata . The species is described in greater detail by Heatubun et al. (2018).

Figures

FIGURE 14. Distribution map of part of the species of the Nengella group of Hydriastele.

FIGURE 17. Hydriastele splendida. A. Habit. B. Leaf. C. Detail of leaf indumentum. D. Portion of stem with infructescence. E. Portion of rachilla with pistillate flowers. F. Pistillate flower whole and in longitudinal section. G. Fruit. Scale bar A = 40 cm; B = 8 cm; C = 1.5 cm; D = 4 cm; E = 7 mm; F = 3.3 mm; G = 5 mm. All from Baker et al. 820. Drawn by Lucy T. Smith.

FIGURE 18. Hydriastele splendida. A–B. Habit. C. Portions of rachillae with pistillate flowers. D. Infructescence. A from Baker et al. 820; B–D from Baker et al. 1443 (cultivated specimen). All photos: W.J. Baker.