| Hydriastele (high-dree-Ah-STEL-eh) |
Heath forest, Mt. Jaya, West Papua, Indonesia. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Habitat and DistributionWidespread in mountainous regions of Papua New Guinea, between (200+) 600 and 1,450 m
Distribution:—The central New Guinea highlands, Goodenough Island and the Torricelli Mountains of Papua New Guinea, and Yapen Island in western New Guinea. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.
Habitat:—Premontane and montane forest on slopes and ridgetops with volcanic soils and limestone, (300–)500–1450 m. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.
Solitary, robust palm to 35 m tall bearing 15–17 leaves in crown. Stem 15–30 cm in diam.; internode 8–10 cm long. Leaf 2.5–3.6 m long including petiole; sheath 1–1.5 m long, covered with a thin layer of lanate, buff indumentum, crownshaft ca. 110–200 × 30 cm; petiole 10–40 cm long, flattened or slightly channelled adaxially; rachis usually strongly arcuate; leaflets (48–)57–70 per side, arranged regularly, ascending and sometimes drooping at their tips, linear; normally with ramenta on the abaxial, basal to middle portion of the midrib; basal leaflets single-fold, acuminate or truncately praemorse apically; middle leaflet 90–125 × 2–3 cm, single-fold, somewhat acuminate or truncately praemorse apically; terminal leaflets comprising 2 or 3 folds, truncately praemorse apically. Inflorescence 60–90 cm long including 10–15 cm peduncle, branched to 2 or 3 orders, apparently protogynous; rachillae ca. 28 (rarely 8–11); triads 4–10 mm apart, opposite and decussate; inflorescences 7–8 present. Staminate flower 13–20 × 3–6 mm in bud (when dry), cream; stamens 8–24. Pistillate flower 2–3 × 2–3 mm in bud (when dry), cream to brownish, with free sepals and free, low and ± rounded petals. Fruit 7–10 × 6–10 mm when ripe, subglobose to broadly ellipsoid, red, with a distinct, dark, sclerotic zone encircling apical stigmatic remains (up to ca. 3 mm in diam.). Seed about 6.5 × 5.5 mm, subglobose; endosperm homogeneous. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.
Tall slender palms to 24 m or more in height; stem l0-25 cm in diameter; leaves 16-19 in a crown, strongly arcuate, sheath 95-120 cm long, petiole 12-20 cm long, blade about 240-250 cm long, petiole and rachis thickly brown-lepidote above and below; pinnae erect: but drooping at the tips, 50 69 on each side of the rachis, 65-95 cm long, 2.I-4 cm wide, deeply bifid at the apex, with the upper margin much prolonged, upper surface minutely and sparsely dotted, the lower surface the same and with several to many large, pale ramenta on the midrib (lacking in Mt. Suckling population). Inflorescence 60-90 cm long, branching to 2 orders, axes and flowers white, glabrous; rachillae about 50-60 cm long, l-4 mm wide, bearing 80-185 triads. Staminate flowers l0-18 mm long, with 9-24 stamens. PistilIate flowers 2-3.5 mm high, with 2-3 staminodes; fruit bright red, subglobose, 7-13 X 4-9 mm when dry; endosperm homogeneous. (Frederick B. Essig 1973) Editing by edric.
Having carefully examined the cited specimens in comparison with the type descriptions for Hydriastele longispatha, Hydriastele crenata, Hydriastele obscura and Hydriastele brossii, I have reached the conclusion that they all representing elements of a single, variable, and widespread species. The examination of the pericarp anatomy of several of the specimens, representing widespread populations, reinforced this conclusion. The specimens examined shared a unique feature in the genus, namely a distinct series of fibrous bundles in the outer pericarp, As far as can be determined, the fruit in this species are all bright red at maturity. Leaves are characteristically strongly arcuate, with pinnae ascending but soft and drooping at the tips. The habitat preference of mountainous terrain for this species contrasts with the lowland habitat of Hydriastele costata. In this regard, however, the locality given for the type collection of Hydriastele longispatha is troublesome and possibly an error. The locality is given vaguely as "the Sepik River, altitude I97 m, November 1910." At 200 m, one is still in lowland alluvial forest, the wrong habitat for this species as currently understood. It is recorded, however (Flora Malesiana l: 478. 1950), that during November (Nov. 2-13) Schultze made a side trip to the mountains south of the Sepik, ascending to Peripetus Peak (alt. I,492 m), which I have not located, but which apparently is in the vicinity of the Leonard Schultze River, 1Q-15 miles east of the Frieda River. This, then would be very close to where I collected the species and observed it in great abundance. It is possible and likely that the type of the species was collected on this side trip at an altitude considerably above 197 m. The populations in the Sepik Basin are homogeneous with respect to stamen number (9), but those in the southern part of the range are more variable. Hydriastele brassii has 20-24 stamens, which at first prompted me to maintain it as a separate species. Other populations bridge the gap, however. The specimen from the Morobe Province has 12 stamens, and the specimens from the Mt. Suckling area have 18. With the addition of the anatomical data from the pericarp, it became evident that Gulubia brassii could no longer be maintained. (Frederick B. Essig 1973)
H. longispatha can be characterized by the presence of a distinct series of fibrous bundles located outside of the tanniniferous zone and apparently not connected with the fibrovascular bundles to the inside of the tanniniferous zone. (Frederick B. Essig 1973)
Cold Hardiness Zone: 10b
Comments and Curiosities
Notes:—Hydriastele longispatha is a robust, emergent palm with arching leaves and about 57–70 ascending leaflets on each side of the rachis. It is distinct from other species treated here due to the combination of the apical leaflet pair with truncately praemorse tips and protogynous inflorescences. Other robust palms in New Guinea and Australia with truncately praemorse apical leaflets have protandrous inflorescences. Hydriastele longispatha is further distinguished by its high variation in stamen number (8–24 stamens) and relatively small (7–10 × 6–10 mm) subglobose to broadly ellipsoid fruits.
Hydriastele longispatha most closely resembles the five robust, protogynous species of Hydriastele that occur in east Melanesia. These taxa are described by Essig (1982) and Baker & Loo (2006), but, in brief, H. macrospadix and H. hombronii from the Solomon Islands have smaller proportions than H. longispatha with only 30–46 leaflets on each side of the rachis, while H. cylindrocarpa from Vanuatu, and H. vitiensis and H. boumae from Fiji, are all distinguished by their white to yellowish fruits.
Based on our study of the material cited here, we concur with Essig (1982) in broadening the circumscription of H. longispatha due to a continuum in stamen variation and homogeneity across other characters. In addition, due to several new collections, characters that were thought to be distinguishing for H. valida, e.g. slightly less arching leaves with stiff and erect leaflets, now fall within the continuum of variation that we accept for H. longispatha, resulting in H. valida being placed in synonymy. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.
Uses:—Used in house construction, especially for flooring. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.
- Glossary of Palm Terms
- MODERN BOTANICAL LATIN
- "Just To Be Clear"
Phonetic spelling of Latin names by edric.
Special thanks to Geoff Stein, (Palmbob) for his hundreds of photos.
Special thanks to Palmweb.org, Dr. John Dransfield, Dr. Bill Baker & team, for their volumes of information and photos.
Glossary of Palm Terms; Based on the glossary in Dransfield, J., N.W. Uhl, C.B. Asmussen-Lange, W.J. Baker, M.M. Harley & C.E. Lewis. 2008. Genera Palmarum - Evolution and Classification of the Palms. Royal Botanic Gardens, Kew. All images copyright of the artists and photographers (see images for credits).
Frederick B. Essig, University of South Florida, Tampa Florida.
PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.
Many Special Thanks to Ed Vaile for his long hours of tireless editing and numerous contributions.