Rattan Palm (Eremospatha macrocarpa)

Description

Clustered slender to moderate palm climbing to 50-75 m, rarely to 150 m. Stems circular in cross-section, without sheaths, 10-18 mm in diameter, with 22-30 mm; internodes 13-16 cm long. Leaf sheath longitudinally striate, sparsely to moderately covered with light brown scale-like indumentum; ocrea entire, - truncate saddle-shaped with a 2.5-4.0 cm rounded lobe adaxial to the leaf; knee absent. Juvenile stems up to 20 m long; stem with sheath, <1.5 cm in diameter; ocrea with distinct linear wrinkle on adaxial side; petiole <1 cm long; leaves bifid, up to 40 cm - 50 cm, deeply notched, lobes sharply triangular; cirrus up to 80 cm long, emerging from the centre; elaminate rachis often present on juvenile stems, 50-75 cm long. Leaves on mature stems sessile, up to 3.5 m long; rachis 1-1.5 m long, abaxially rounded, adaxially flattened, becoming trapezoid then rounded in cross-section distally, armed along the margins with inequidistant, reflexed thorns, becoming sparsely armed distally, underside of rachis with sparse light brown indumentum; cirrus 1.2-2 m long, unarmed; leaflets, up to 25 pairs on each side of the rachis, linear-lanceolate, abruptly contracted at the base, irregularly and narrowly praemorse at apex, 22-35 cm long - 2-2.5 cm broad at the widest point, concolorous, with 5-7 inconspicuous transverse veinlets 1-2 mm apart, armed along the margins with inequidistant, curved, forward-facing brown-tan spines; lowermost leaflets, smaller than the rest, linear-ovate, reflexed and laxly clasping the stem; acanthophylls ca.3 cm long, parallel to cirrus. Inflorescence glabrous, up to 55 cm long; peduncle 10-15 cm long; rachis 25-40 cm long, arching outwards, rarely straight; rachis bracts, acuminate, opposite proximally, alternate distally, 1-3 mm long, decreasing distally; rachillae distichous, arching vertically, sometimes horizontal, straight, 10-14 on each side, 12-18 cm long, decreasing distally, adnate to the inflorescence axis for 0.5-1.5 mm, with <1 mm-long triangular incomplete bracts subtending each dyad. Flowers borne in close pairs; calyx 3 mm long - 6 mm wide at the mouth, with 3 distinct, rounded, lobes; corolla 10 mm long - 4 mm wide, divided to - of its length; stamens united into 5 mm-long epipetalous ring; free filaments <0.5 mm; anthers <1 mm long; ovary 4 mm - 2.5 mm tipped with ca.2 mm-long style. Fruit at maturity 1-seeded, rarely 2-seeded, - cylindrical, 2.2-2.6 cm long - 1-1.5 cm wide, with 17-24 rows of vertical scales. Seed compressed, 1.8-2 cm long - 1.4-1.8 cm wide - 1 cm thick, flattened on one side or with a shallow depression, embryo lateral, raised, opposite the flattened side. (T.C.H Sunderland, A taxonomic revision of the rattans of Africa (Arecaceae: Calamoideae) in Phytotaxa 51. 2012)/Palmweb. Editing by edric.