Hydriastele costata

Hydriastele (hy-dree-Ah-STEL-eh) costata (cohs-TAH-tah)
Towards north Biak, Papua, Biak, Indonesia. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Scientific Classification
Genus: Hydriastele (hy-dree-Ah-STEL-eh) Species: costata (cohs-TAH-tah)
Synonyms
None set.
Native Continent
Oceania
Morphology
Habit: Solitary Leaf type: Pinnate
Culture
Survivability index
Common names
Cape York Palm. Avos/Afos (Miyah), Bay (Marap), Kaparo (Wandamen), Korr (Jal), Mabla (Orne), Oratare (Sumuri), Poi (Wapi), Tab (Timbunke), Tabavo Nyi (Unknown dialect, North Cyclops Mts. area), Tabuh (Maprik), Yawa (Ambakanja).

Habitat and Distribution

Ubiquitous in lowland New Guinea, also found in the Aru Islands, Bismarck Archipelago,

Biak, West Papua, Indonesia. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.

and northeastern Queensland. H. costata is one of the most common and abundant palms in lowland New Guinea. The species occurs on mesic, well-drained soils in hilly terrain as well as in swampy or seasonally flooded situations.

Distribution:—Widely distributed in the north eastern portion of Cape York Peninsula in Queensland, Australia, and throughout lowland New Guinea and adjacent islands. Also reported from the Bismarck Archipelago (Essig 1982). PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Habitat:—Primary or secondary lowland rainforest often on swampy ground, or more infrequently lower montane forest on less waterlogged ridges and slopes, 0–700 m. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Description

Solitary, robust to very robust palm, to 35 m tall bearing 12–25 leaves in crown, crown distinctively spherical. Stem 15–35 cm in diam. Leaf 2.4–5.5 m long including petiole; sheath 50–180 cm long; petiole 10–60 cm long; rachis straight or slightly drooping; leaflets 58–75 per side, arranged regularly, single-fold, pendulous, linear and acuminate to briefly bifid apically; with ramenta attached to the basal portion of the abaxial side of the midrib; middle leaflet 90–130 × 3–5 cm. Inflorescence 58–100 cm long including 5–25 cm peduncle, branched to 2 or 3 orders, apparently protogynous; triads 1–5 mm apart, opposite and decussate. Staminate flower 6–8 × 2–3 mm in bud, white to brownish; stamens 6, not exposed in bud. Pistillate flower about 2 × 2.5–3 mm in bud, cream, with free sepals and free, low and ± rounded petals. Fruit ca. 8–10 × 6 mm when ripe, ellipsoid, ripening through reddish brown to dark purple or blackish maroon, with conspicuous longitudinal white-greyish stripes, with inconspicuous sclerotic zone encircling apical stigmatic remains (up to ca. 1 mm in diam.). Seed about 5.5 × 4.5 mm, ellipsoid, costate; endosperm homogeneous. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Notes:—Hydriastele costata is the commonest lowland tree palm in New Guinea. It is immediately recognisable as a canopy emergent with a distinctive, spherical crown of more-or-less straight leaves with pendulous leaflets. Its highly distinctive longitudinally striped fruits with costate seeds are not seen in any other member of the genus. Hydriastele costata has a similar habit to H. procera and H. wosimiensis from the Longispatha group. Hydriastele costata appears to be most similar to H. moluccana, a rarely collected species known from North Maluku Province in Indonesia. Hydriastele costata is distinguished from this species primarily by its striped fruits with costate seeds (see Essig 1982). PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press

Tall, moderate palm to 20 m or more in height; stem 20-30 cm in diameter; leaf sheath 75-150 cm long, green, tinged with lilac, glabrous to finely light-brown tomentose near the tip, petiole3 5-60 cm long, blade 220-420 cm long, petiole and rachis finely white-woolly and brown-lepidote above and below, pinnae pendulous, 43-77 on each side, 97-127 cm long, 5.5 cm wide with the apex deeply bifid (or hooded in life), upper surface glabrous, lower surface minutely brown-dotted and with large, whitish, basifixed ramenta along the lower third of the midrib. Inflorescence branching to 2-3 orders, 70-125 cm long, the upper peduncular and rameal bracts rudimentary, triangular to 6 mm long or represented only by horizontal scars; rachillae straight or sometimes somewhat flexuous, to 62 cm long, 2-3 mm thick, bearing up to 280 triads Staminate flowers cream-colored, soapy scented, 6-7 mm long, stamens 6, shorter than the petals, pistillate flowers 1.5 mm high, flushed with pink; fruit 7-9 X 4.5-5 mm, blue-gray with whitish stripes over prominent fibrous ribs; endosperm homogeneous. (Frederick B. Essig 1973) Editing by edric.

Culture

Cold Hardiness Zone: 10b

Comments and Curiosities

Uses:—Stems and leaves used for flooring and house construction, leaf sheaths used as basins for water buckets, carrying baskets, sago containers and plates, indumentum used as firelighter and old inflorescences as brushes. The palm heart is consumed. Commonly planted near villages. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Vernacular names:—Avos/Afos (Miyah), Bay (Marap), Kaparo (Wandamen), Korr (Jal), Mabla (Orne), Oratare (Sumuri), Poi (Wapi), Tab (Timbunke), Tabavo Nyi (Unknown dialect, North Cyclops Mts. area), Tabuh (Maprik), Yawa (Ambakanja). PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Conservation status:—Least Concern (LC). Hydriastele costata is widely distributed (EOO > 1,360,000 km2 ) and common. The AOO (136 km2 ) is higher than for most other species within the genus yet still likely to be a conservative figure. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

In Queensland H. costata occurs in a few sites on the extreme north of Cape York Peninsula, in the township of Bamaga and through the "Four Mile Scrub" along the road to Somerset, along several streams draining into Newcastle Bay just south of Somerset and sporadically in various other sites in that region. Further south along the east coast of the Peninsula there are several populations around Iron Range in the Lockhart River region. Around Bamaga the palm attains its best form, it is a tall and very handsome single trunked tree reaching to 30 m or more. It favours moist places on seasonally flooded flats or on steep slopes in volcanic soils.