Phoenix roebelenii O'Brien

Conservation

A naturally restricted distribution, habitat loss and a horticultural trade in wild-collected plants may mean that the wild populations of P. roebelenii merit 'vulnerable' status, but further studies are needed. Demand for P. roebelenii as an ornamental is mostly met through seeds and offshoots from cultivated plants. However, Barrow (1994) suggested that collection of mature palms from the wild poses an increasing threat.

General Description

Clustering palms (often solitary in cultivation), forming clumps with stemless plants suckering at base of taller stems. Stem 1 - 2 m (rarely 3 m) high, without sheaths to 10 cm in diam., erect or twisted, pale, becoming smooth with age, marked with diamond-shaped persistent leaf bases each with a central bump of remnant vascular tissue; stem base developed with a root boss; roots occasionally emerging from stem above ground level. Leaves arching, 1 - 1.5 (2) m long; pseudopetiole to c. 50 cm long; leaf sheath reddish-brown, fibrous; acanthophylls arranged singly or paired, c. 12 on each side of rachis, orange-green, to 8 cm long; leaflets regularly arranged, opposite, c. 25 - 50 on each side of rachis, linear, concolorous, deep green, often flaccid, to 40 x 1.2 cm; lamina with discontinuous white scurfy ramenta along abaxial veins and midrib, almost totally covering abaxial surface of unexpanded (sword) leaves. Staminate inflorescences pendulous; prophyll coriaceous, two-keeled, splitting once abaxially between keels, c. 30- 60 cm long; peduncle to 30 cm long; rachillae 7- 20 cm long. Staminate flowers with calyx a three-pointed cupule, 1.2 mm high, yellow- white; petals pale yellow-white with acuminate apices and with jagged margins, 7 - 8 x 2 - 2.5 mm; anthers 3.5 - 4 mm long. Pistillate inflorescences erect, arching as fruits ripen, up to 35 cm long; prophyll coriaceous, two-keeled, to 35 cm long x c. 5 cm wide, splitting once adaxially between keels to reveal inflorescence; peduncle green, to c. 30 x 3 cm; rachillae with bulbous bases, orange-green, occasionally branched to one order, subtended by papery bracts (c. 4 cm long). Pistillate flowers pale green, arranged in distal three quarters of rachilla, subtended by papery bracts to 5 mm long; calyx a three-pointed cupule, thickened and ridged up to apices, striate, 2 - 2.5 mm high; petals 3.5 x 4 mm with acute apices; generally only one carpel reaching maturity. Fruits obovoid, with persistent perianth, maturing from dark green to purplish brown, 13 - 18 x 6 - 7 mm; stigmatic remains apical, 1 mm long, orange- brown, often recurved. Seed narrowly elongate, terete, with rounded apices, 7 - 3 mm; embryo lateral opposite raphe; endosperm homogeneous.

Vernacular

THAILAND. Paam sipsong pannaa (Xishuangbanna palm), [Smitinand (1948)]. VIETNAM. Cha rang (Moyenne Region), [Magalon (1930)].

Biology

Closely associated with riverside or cliff habitats where it grows as a rheophyte. The rheophytic habit is rare within the palm family (Dransfield 1992). The clustering habit of R roebelenii may help it to survive flooding.

Distribution

Northern Laos (Nam Ou valley), Vietnam (Upper Black R. region near Lai-Chau), and southern China (Xisuangbanna region of Yunnan), most notably along the banks of the R. Mekong.

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

Distribution

Cultivated in Colombia. Colombian departments: Antioquia, Bogotá DC, Cundinamarca, Tolima, Valle del Cauca.

Habit

Shrub, Solitary palm.

Ecology

Habitat according IUCN Habitats Classification: forest and woodland, shrubland, artificial - terrestrial.

Bernal, R., Gradstein, S.R. & Celis, M. (eds.). 2015. Catálogo de plantas y líquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá. http://catalogoplantasdecolombia.unal.edu.co

Distribution

Cultivada en Colombia.

Morphology General Habit

Arbusto, palma solitaria

Use Environmental

Environmental uses.

Use Gene Sources

Used as gene sources.

Use Food

Used for food.