Beccariophoenix fenestralis

Family: Arecaceae    Palm Tree

Common Name: Giant Window Palm

Cold Hardiness Zone: 10b     View the UK and US zone maps

Identification:
This is the Beccariophoenix formally recognised as the "windowed" B. madagascariensis. It has now been recognised as a separate species (Dransfield & Rakotoarinivo, Palms, 2014). It differs from B. madagascariensis in that the sessile inflorescences are always infrafoliar, not interfoliar as in B. madagascariensis; pointed staminate flower buds, not blunted; and of-course the characteristic seedling morphology where it has broader leaflets with the distal-most joined to form a broad bifid fan or flabellum but partially split near the rachis to produce conspicuous windows.

General Information:
Large single-stemmed tree palm. Stem erect, to 15 m tall, 34 cm diameter, dull grey brown with conspicuous leaf scars, internodes to 5 cm long, in cultivation often with a dense mass of orange-brown adventitious roots forming a boss at the base of the stem. Leaves 18-25 in crown, pinnate, marcescent in juvenile palms in cultivation, abscising neatly in adult palms, spirally arranged; leaf sheath with base of leaf axis 150-165 cm long with a true petiole only 9 cm long, 10 cm wide and 5 cm thick, adaxially channeled, abaxially rounded; sheath fibrous; whole leaf ca. 6 m long, including the apparent petiole; rachis 300-320 cm long; leaflets 150-170 on each side of the rachis, regularly arranged but held rather untidily in one plane; basal leaflets 59-68 x 1.5-1.7 cm, mid-leaf leaflets 105-118 x 6.5-7.5 cm, apical leaflets 44-46 x 1-1.1 cm; leaflets with thin white wax on both surfaces, adaxially glabrous, abaxially with abundant pale brown ramenta along midribs and with abundant minute punctiform scales along minor veins, transverse veinlets conspicuous. Inflorescence solitary, infrafoliar at anthesis; 62-90 cm long, branching to 1(-2) order; peduncle 10-15 cm long, to 25 cm wide at the very base, flattened and winged; prophyll not seen; peduncular bract to 70 x 20 cm, boat-shaped, woody, ca. 12 mm thick, adaxially smooth, deeply grooved abaxially and covered with a dense layer of reddish brown indumentum, the bract tapering to a blunt tip ca. 2.5 cm wide, the whole bract circumscissile, leaving a broad scar on the peduncle; rachis 7-9 cm long; rachillae very crowded, spirally arranged, up to 40, 35-56 cm long, occasionally branched, each subtended by a triangular striate rachis bract 1.7-2.2 x 1.0-1.4 cm, basally swollen, with scattered caducous brown scales and thin white wax, 4-7 mm diam., sometimes with a basal portion to 11.5 cm long devoid of flowers, then a portion up to 25 cm long bearing triads, distally the rachillae bearing paired or solitary staminate flowers only, flower groupings distichously arranged; rachilla bracts triangular, 1-4 x 1-2 mm. Staminate flowers pale yellow, more or less symmetrical and pointed in bud, 1.85 x 0.7 cm; sepals 3 x 2 mm, imbricate, shallowly triangular, connate at the very base; petals stiff, almost woody, 18 x 6-7 mm, elliptic with conspicuous triangular acuminate tips, drying inconspicuously striate and with thin white wax; stamens 18-20, filaments ca. 1 mm long, anthers 8-12 mm long, ca. 1 mm wide; pistillode inconspicuous, conical, less than 1 mm high. Pistillate flower 15 x 9 mm; sepals distinct, 10 x 9 mm, imbricate; petals 9 x 8 mm, similar to petals, but with short valvate tips; staminodal ring ca. 0.1 mm high with ca. 9 teeth; gynoecium ellipsoidal, 13 x 4 mm. Mature fruit dark purple, obpyriform, to 4 x 2.5 cm, including the pyramidal apical beak to 9 x 12 mm, tipped with short stigmatic remains to 4 x 4 mm; epicarp smooth when fresh, becoming striate when dry, glabrous; mesocarp ca. 2 mm thick; endocarp very thin, fragile, ellipsoidal, ca. 25 x 20 mm, distally with three low ridges, pores obscure. Seed ellipsoidal, ca. 24 x 19 mm; endosperm deeply ruminate; embryo lateral. Eophyll and first few leaves lanceolate, undivided; subsequent seedling leaves with a broad apical, furcate flabellum composed of up to 30 folds, the margin deeply lobed, the lobes corresponding to the adaxial folds, basally split along the abaxial folds to ca. 2/3 to 3/4 the length of the folds, the whole thus appearing "windowed."

Distribution:

Native to, Madagascar

Originally only known from the single tree by the roadside at Ranomafana Est 18º58’5.76”S 48º51’16.86”E. Then in 2005 another population was discovered about 17 km SW from the single tree, growing among graves. It is quite probable that it is the graves that has saved this Critically Endangered species as the palm has traditionally been felled for its edible palm-heart. Occurs on highly disturbed remnant vegetation with lateritic soils rich in organic matter, elevation 60-160 m. This palm occurs at the lowest elevation of any Beccariophoenix, thus making it the least hardy (10b), although it is the fastest growing in cultivation and the best suited as a house-plant.

Location: Madagascar (-18.972029°N, 48.868477°E)

Observations
Map may not represent the complete natural distribution. (Markers display observation data).
Beccariophoenix fenestralis Overlay Image ©2017 Trebrown - No re-distribution without permission.


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