Arenga australasica (H.Wendl. & Drude) S.T.Blake ex H.E.Moore

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

Moderate to robust, multi-stemmed tree palm to 4–8 (–14 m)

Morphology Stem

Stem ca. 12 cm diam. or more, dying after flowering and fruiting, obscured by old leaf-sheaths and abundant black fibre, crownshaft absent

Morphology Leaves

Leaf 5–10 in crown, erect to spreading, to ca. 6 m long; petiole and sheath to 25–40(–100) cm long, the petiole with abundant grey indumentum, sheath disintegrating into an untidy mass of robust black fibres to 50 cm long; leaflets 40–70 on each side of leaf rachis, to 40–110 × 2–5 cm long, with jagged tips, arranged irregularly, grouped in 2s–4s in mid section, dark green on upper surface, covered in pale indumentum on lower surface, leaflet base briefly stalked and with an asymmetric ear-like lobe

Morphology Reproductive morphology Inflorescences

Inflorescences branched to 1 (rarely 2) orders, male and female very similar but female more robust, to 1.7 m long, male inflorescences occasionally multiple; rachillae 45–80 cm long, 6 mm diam. in female, 5 mm diam. in male

Morphology Reproductive morphology Flowers

Female flower spherical, ca. 6 mm diam. Fruit spherical, dull green, ripening white then red, 1.5–1.8 cm diam. Seed 1–3, 7–11 × 4 mm, with two flattened sides and one curved side, surrounded by irritant crystals; endosperm homogeneous, embryo lateral. Male flower bullet-shaped, 6–10 × 4–6 mm; stamens ca. 14–24

Distribution

Widespread in New Guinea, also in Maluku and Australia.

Ecology

Lowland forest, particularly along riverbanks and occasionally at higher elevations to 640 m.

Vernacular

An (Sough), Biawar (Wamesa), Go-ih (Matapaili), Iri Nyi (North Cyclops).

Conservation

Least Concern.

Note

Arenga microcarpa is a widespread, somewhat weedy palm occurring widely in the lowlands of New Guinea. It is very variable, perhaps related to soil fertility and exposure. In moist sites, particularly along river banks, it can be very robust, but surviving in cleared areas, it can be stunted. Some Australian populations have been separated as a distinct species, A. australasica (see Mogea 1991 and discussion in Dowe 2010), but the characters separating the two taxa overlap and phylogenetic analyses conducted by Jeanson (2011) suggest there is but one variable species.

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