Hydriastele dransfieldii

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Hydriastele (high-dree-Ah-STEL-eh)
dransfieldii (dranz-feeld'-ee)
041d5644-906f-4502-89e4-e3b65d2925dc.jpg
Fairchild Tropical Garden, Florida. Photo by Dr. Scott Zona/Palmweb.
Scientific Classification
Genus: Hydriastele (high-dree-Ah-STEL-eh)
Species:
dransfieldii (dranz-feeld'-ee)
Synonyms
None set.
Native Continent
Oceania
Oceania.gif
Morphology
Habit: Solitary
Leaf type: Pinnate
Culture
Survivability index
Common names
Ombrush (Biak language).

Habitat and Distribution

Distribution:—Biak Islands (Biak, Supiori and Numfoor; Baker & Heatubun 2012). Habitat:—Lowland, primary or secondary rainforest on rocky limestone ridges and slopes, often with a very thin layer of topsoil, 0–300 m. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Papua New Guinea, Biak Island. Reported from Supiori and Numfoor Islands by
Forest on limestone along Jalan, Papua, Biak, Indonesia. Photo by Dr. William J. Baker, Royal Botanic Gardens, Kew/Palmweb.
Biak islanders. In forest on limestone between sea level and 310 m, often growing in very thin soils and occasionally in cracks in limestone.

Description

Solitary, moderately slender palm to 12 m tall, bearing 6–10 leaves in crown. Stem 5–12 cm in diam. Leaf 1.3–3 m long including petiole; sheath 35–80 cm long; petiole 10–65 cm long; lamina typically with 3 broad, multi-fold leaflets interspersed with a few single-fold leaflets each side of rachis; leaflets oblong to linear, truncately praemorse apically. Inflorescence 37–52 cm long including 2–5 cm peduncle, branched to 1 order, protandrous; rachillae 4–11, yellowishgreen; triads largely opposite and decussate. Staminate flower 9–11 × 2–5 mm in bud, green to white; stamens (9– )13–16. Pistillate flower ca. 9 × 5 mm in bud, with fused, greenish-white sepals forming a cylindrical tube, and white petals fused in lower half with conspicuous, triangular and valvate tips. Fruit ca. 18 × 12 mm when ripe, obovoid, red, with a distinct, dark, shallowly concave, sclerotic zone encircling apical stigmatic remains (up to ca. 5 mm in diam.). Seed ca. 8 × 7 mm, subglobose; endosperm ruminate. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Solitary, pleonanthic, moderately robust palm; stems up to 1,2 m tall, 5-12 cm in diam.; internodes 3.0-1 1.5 cm long, nodal scars not always conspicuous. Leaves 6-10 in the crown, pinnate, 1.3-3.0 m long (including petiole), neatly abscising; sheaths tubular, 35-80 cm long, covered with thin, finely floccose, dark brown indumentum; crownshaft well defined, up to 12O cm long and up to 20 cm in diam.; petiole 10-65 cm long and 1.5-3.0 cm in diam., channeled adaxially, rounded abaxially, indumentose at junction with sheath, otherwise with copious minute, dark scales; rachis somewhat arching, with adaxial longitudinal ridge, rounded abaxially, indumentose as sheath, indumentum sometimes more dense and coarse than on sheath, sometimes absent with only scattered scales remaining, indumentum possibly lost with age; blade variously divided into 1-19 fold leaflets, typically including 3 pairs of multiple-fold leaflets, interspersed with very few pairs of single-fold leaflets; leaflet with praemorse apical margin, 65-130 cm long, 1.5-30 cm wide, individual folds 1.5-3.5 cm wide, terminal pair of leaflets always multiple-fold (about 10-14 folds) forming flabellum with cleft apex; Iamina with numerous minute brown dots on both sides, transverse veinlets inconspicuous, adaxial surface paler when dried, main veins with very few minute hairs adaxially and brown ramenta abaxially. Inflorescence infrafoliar, 37-41, cm long at anthesis, apparently growing to about 52 cm long in fruit, protandrous, branching to 1 order; peduncle 2-5 cm long, glabrous; prophyll 43-46 cm long, 5-8 cm wide, borne about half way up the peduncle, tubular, lanceolate, Z-keeled, membranous, glabrous, entirely enclosing the inflorescence, then splitting longitudinally and falling before staminate anthesis; peduncular bracts 1-3, first peduncular bract borne 8-10 mm above the prophyll, similar to the prophyll in shape and size, but lacking keels, remaining peduncular bracts inconspicuous and incomplete; rachis 1-2 cm long; rachis bracts inconspicuous, incompletely sheathing; rachillae 4-LI, 30-36 cm long at anthesis, apparently growing to about 49 cm long in fruit, 2.0-3.5 mm wide, borne at a very acute angle to the rachis, apparently rather stiff and straight, or pendulous when heavy with fruit, sometimes sinuous in distal-most portion, bearing triads in opposite and decussate pairs, except in distal-most and proximal-most portion of rachilla where arranged spirally, triads 4-6 mm apart; rachilla bracts very inconspicuous, low, rounded; floral bracteoles low, rounded, similar to rachilla bract. Staminate flowers 9-11 mm long, asymmetrical; sepals 3, greenish white, connate, triangular, 2 mm long; petals 3, white, briefly connate at the base, falcate, acuminate, much exceeding the calyx, 1 petal much larger than the others, 10-11 x 4-5 mm, smaller petals 9-10 x 2-3 mm; stamens 13-16 (very rarely as few as 9); filaments slender, about 0.5 mm long, sometimes briefly epipetalous near base of petal; anthers linear, 5-6.5 mm long, about 0.6 mm wide, basifixed, dehiscence latrorse, connective prolonged into an acute appendage, about 0.5 mm long; pollen unknown; pistillode absent. Pistillate flowers about 9 x 5 mm long at anthesis, perianth apparently continuing to grow as fruit develops, flower scar 2.5-4 x,2-3 mm; calyx greenish white, synsepalous, forming cylindrical tube, about 3 mm long, about 5 mm wide, margin with 3 very short lobes; corolla white about 8.5 mm long, about 5 mm wide, sympetalous for half its length, with 3 free lobes, the two parts separated by a dark equatorial ridge (visible only in herbarium material); corolla lobes about 4 mm long, very thick, valvate, tightly closed during staminate anthesis, adaxial surface thrown into minute folds and tubercles, drytng after pistillate anthesis, becoming hard and brittle, and often caducous; staminodes 3-5(6?), minute, triangular; gynoecium white, 5.5 mm long, 3.5 mm wide, obovoid, uniloculaq uniovulate, locule located near the base of the ovary, ovary wall rather fibrous; stigmas 3, lobes less than 1 mm long, fleshy, slightly recurved, stigmatic surface forming deep, narrow invagination into the ovary wall at the iunction of the 3 lobes. Fruit obovoid, about 18 mm long, about 12 mm wide, with conspicuous woody discoid depression at apex, about 5 mm in diam., stigmatic remains persistent in centre of depression, perianth persistent, corolla lobes becoming hardened with age and often caducous; epicarp smooth, thin, ripening through yellow to red when mature, with copious tannin bodies beneath; mesocarp fibrous, about 1 mm thick, but much thicker below stigmatic remains; endocarp very thin, adhering closely to seed; seed subglobose, about 8 x 7 mm, with small basal depression and shallow longitudinal groove; endosperm deeply ruminate; embryo basal. (W.J. Baker, R.A. Maturbongs, J. Wanggai and G.G. Hambali. 2000)/Palmweb. Editing by edric.

Culture

Cold Hardiness Zone: 10b

Comments and Curiosities

Notes:—Hydriastele dransfieldii is a moderately slender midstorey palm only known from the Biak Islands in western New Guinea. The species is highly distinctive vegetatively as well as in its reproductive structures. It has leaves usually consisting of three broad, multi-fold leaflets interspersed with a few single-fold leaflets and inflorescences branched to 1 order, which is unusual for Hydriastele inflorescences of more than 30 cm in length. The sepals of the pistillate flower are fused forming a conspicuous cup, and similarly the petals are fused at their bases. These features are known in only one other species, H. beguinii (Burret) Baker & Loo (2004: 62), from North Maluku Province, which is the sister taxon of H. dransfieldii (Loo et al. 2006). Previously, the two species were placed in the genus Siphokentia, which was subsumed within Hydriastele (Baker & Loo 2004). The two species can be separated based on multiple characters of the leaves and inflorescences (see Baker et al. 2000). PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Vernacular names:—Ombrush (Biak). PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Conservation status:—Least Concern (LC). This species has a relatively narrow distribution (ca. 6,500 km2) but has been observed to be common in many parts of Biak (Baker & Heatubun 2012) and the AOO (20 km2) is no doubt a low estimate resulting from under-collecting. PETER PETOE, CHARLIE D. HEATUBUN & WILLIAM J. BAKER Phytotaxa 370 (1) © 2018 Magnolia Press.

Etymology: The species is named for John Dransfield (eminent English palm botanist) in recognition of his monumental contribution to the taxonomy of palms in Southeast Asia. (W.J. Baker, R.A. Maturbongs, J. Wanggai and G.G. Hambali. 2000)/Palmweb.

Uses: Seed as substitute for betel nut, leaves for wrapping meat or sago. (W.J. Baker, R.A. Maturbongs, J. Wanggai and G.G. Hambali. 2000)/Palmweb.



External Links

References

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).

Baker, W.J. , Maturbongs, R.A. , Wanggai, J. & Hambali, G.G. 2000. Siphokentia. Palms 44(4) 175-181.

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.

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