Rhopaloblaste ledermanniana Becc.

Baker, W.J., Barfod, A.S., Cámara-Leret, R., Dowe, J.L., Heatubun, C.D., Petoe, P., Turner, J.H., Zona, S. & Dransfield, J. (2024) Palms of New Guinea. Royal Botanic Gardens, Kew, Richmond. 726 pp.

Morphology General Habit

Moderately robust, single-stemmed palm to 15 m, bearing up to 11 leaves in crown

Morphology Stem

Stem 8–11(–15) cm diam., internodes 6–8 cm

Morphology Leaves

Leaf 2.2–4 m long including petiole; sheath 62–70 cm long; petiole 15–20 cm long; leaflets 59–90 each side of rachis, linear, lower surface with twisted ramenta on midrib; mid-leaf leaflet 64–75 × 2.3–2.5 cm wide

Morphology Reproductive morphology Inflorescences

Inflorescence 64–95 cm long including 1.5–4 cm peduncle, widely spreading with basal branches strongly recurved, branched to 4 (rarely 5) orders; primary branches ca. 18, to 70 cm long; rachillae 17–36 cm long, 2–2.9 mm diam. Male flower 5–6 × 3–4 mm at anthesis; stamens 6

Morphology Reproductive morphology Flowers

Female flower 2–3 × 3–3.5 mm

Morphology Reproductive morphology Fruits

Fruit 15–21 mm × 9–12 mm, ellipsoid- ovoid, yellow to orange-red

Morphology Reproductive morphology Seeds

Seed 10–12 mm × 8–10 mm.

Distribution

Widespread from north-western to central New Guinea, including the Raja Ampat Islands.

Ecology

Primary forest from sea level to 1,000 m.

Vernacular

Black Palm (Mian), Flim saku (Mian), Imbetor (Wandamen), Kasira (Wandamen), Koah (Nomad), Kofa (Meyah), Kuwehleh (Orne), Mimini (Kamoro), Res (Biak), Saku (Mian).

Conservation

Least Concern (IUCN 2021).

Note

Rhopaloblaste ledermanniana can be distinguished by its small ovoid-ellipsoid fruits, by its slender rachillae and by the inflorescence branching to four or sometimes five orders. It is the most widely encountered species of Rhopaloblaste in New Guinea, being widespread though rarely abundant.

IUCN Red List of Threatened Species https://www.iucnredlist.org/species/189125899/189758742

Conservation

LC - least concern

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

Banka, R., & Baker, W. (2004). A Monograph of the Genus Rhopaloblaste (Arecaceae). Kew Bulletin, 59(1), 47-60. doi:10.2307/4111073

Type

Papua New Guinea, East Sepik Province, April River, Nov. 1912, Ledermann 9718 (syntype B†), Sept. 1912, Ledermann 8648 (syntype B†), Sept. 1912, Ledermann 8708 (neotype, here designated, K!).

Morphology General Habit

Moderately robust, mid-storey, solitary palm bearing up to 11 leaves in the crown

Morphology Stem

Stem to 15 m tall, 8 - 10(- 15) cm diam., surface slightly rough with longitudinal grooves, dark olive-green, becoming brownish black with age, leaf scars prominent, internodes 6 - 8 cm

Morphology Leaves

Leaf sheath 62 - 70(- 100) cm long, with dense greyish brown lepidote tomentum; crownshaft 62 - 130 cm long, c. 9 - 12 cm wide; petiole 15 - 20 cm long, concave on adaxial surface, greyish brown; rachis 2 - 3.8 m long, with blackish membranous scales on the adaxial surface; leaflets 59 - 90 each side of rachis, borne 2.5 - 4 cm apart, in one plane, semi-pendulous, middle leaflets 64 - 75 x 2.3 - 2.5 cm, linear, tapering acutely and bifid at the apex, discolorous, with twisted, medifixed or basifixed ramenta on abaxial surface of mid-veins, membranous scales as on rachis on adaxial surface of mid-veins near base of leaflets

Morphology Reproductive morphology Inflorescences

Inflorescence 64 - 95 cm long, with a spread of 1.2 - 1.5 m, divaricate, branched to 4 or very rarely 5 orders, primary branches c. 18, 50 - 70 cm long, basal pair of primary branches strongly recurved; prophyll 26 - 37 cm long, 6 - 9 cm wide, with greyish brown, silky tomentum; peduncle 1.5 - 4 cm long, 4 - 6 cm diam., green with scattered reddish brown indumentum; rachillae slender, 17 - 36 cm long, 2 - 2.9 mm in diameter, greenish

Morphology Reproductive morphology Flowers

Staminate flower 5 - 6 mm long, 3 - 4 mm diam. at anthesis; sepals 2 - 2.3 x 2.3 - 2.5 mm, rounded, striated near the margins; petals 3.6 - 4 x 2 - 2.2 mm, elliptic, glabrous; stamens 6, 5.3 - 5.6 mm long, filaments 3 - 3.5 mm long, connate at the base, anthers 2.1 - 2.5 mm long, 0.6 - 0.8 mm wide, elliptic, medifixed; pistillode conical, 3.2 - 3.5 mm long, 1 - 1.1 mm diam. at base Pistillate flower 2 - 3 mm long, 3 - 3.5 mm diam., borne throughout the rachillae; sepals 1.4 - 1.5 mm long, 2.4 - 2.5 mm wide, rounded; petals 2.7 - 2.8 mm long, 1.5 - 1.8 mm diam., rounded with short triangular tips; staminodes 4, lobes 0.4 - 0.5 mm long, 0.4 - 0.5 mm wide at the base, acute at the apex; gynoecium 2.8 - 3 mm long, 1.9 - 2.1 mm diam., ovoid

Morphology Reproductive morphology Fruits

Fruit 15.5 - 21 mm long, 9.5 - 12 mm diam., ovoid-ellipsoid, yellowish green when immature, becoming orange- red in maturity, with cupule of persistent perianth 5 - 6 mm long

Morphology Reproductive morphology Seeds

Seed 10 - 12 mm long, 8 - 10 mm diam., ellipsoid-ovoid, testa black.

Distribution

From Waigeo Island, through west New Guinea as far as Sandaun and Western Provinces of Papua New Guinea.

Ecology

Primary rain forest with sparse undergrowth on ridges and gentle slopes, sometimes also occurring on alluvial flats near streams, from 50 to 900 m above sea level.

Vernacular

Black Palm (Papua New Guinea). Mimini (Yamur dialect, Etna Bay), Imbetor, Kasira (both Wandammen), Kuwehleh (Orne dialect, Aitape), Saku (Mianmin dialect, Telefomin), Koah (Nomad).

Conservation

Least concern. Rhopaloblaste ledermanniana is under no threat in West Papua as it has a wide distribution there. It is however restricted to the north-western and central-western part of Papua New Guinea, and does not extend towards the eastern most part of Papua New Guinea. The species may become threatened in Papua New Guinea if heavily disturbed in its limited, localised distribution there.

Note

Rhopaloblaste ledermanniana can be distinguished by its small ovoid-ellipsoid fruits, by its slender rachillae and by the inflorescence branching to four or sometimes five orders. Rhopaloblaste ledermanniana was first described by Beccari, based on two Ledermann collections (9718 and 8648) from the April River (April Flusse). Both of these specimens were held in Berlin and have been destroyed. Beccari's protologue was published posthumously in Botanische Jahrbficher, edited by Lauterbach (1923). After the description of the new species Lauterbach added a note that a third specimen (Ledermann 8708), we assume in Berlin, also from the April River, had been annotated by Beccari as Rhopaloblaste ledermanniana. The specimen seen by Lauterbach was also destroyed, but a duplicate of this collection is still extant in Kew and is an obvious choice as the neotype of the species.

Use

The hard, outer part of the stem is used for making floorboards, walls, bows and arrow tips. The shoot apex is eaten in Mianmin and Wasior. The fruit are eaten by the Mianmin people.

Use

The hard, outer part of the stem is used for making floorboards, bows and arrow tips. The shoot apex is eaten in Mianmin (Papua New Guinea) and Wasior (West Papua).