Pandanus amaryllifolius has two distinct growth forms:-

Small growth form: Perpetuated sucker shoots. Stem slender, 1-1.6 m tall, 2-5 cm in diameter, decumbent and ascending, emitting aerial roots throughout its length. Leaves oblong, 25-75 cm x 2-5 cm, rather pale green, somewhat thin and flaccid, more or less glaucous and keeled beneath, the apex with rather distinct twin lateral pleats, the margins entire, unarmed except a few minute prickles less than 1 mm long near the apex. Flowers and fruits unknown.

Large growth form: Eventually producing an erect stem, 2-4.5 m tall, 15 cm in diameter, unbranched or sparsely branched, bearing large aerial prop roots. Leaves oblong, 150-220 cm x 7-9 cm, apex acute, rather dark green above, glaucous and keeled beneath, the twin lateral pleats above somewhat prominent, margins entire, unarmed except near leaf apex with small antrorse prickles about 1 mm long and very rarely with 1-3 small stout prickles near the base. Inflorescence (evidently exceedingly rare), probably pendent, up to 60 cm long, the spathes 90 cm long, white or the lower ones with green foliaceous tips, bearing several oblong spikes to 35 cm long or more, several cm wide; upper ones much shorter, about 9-10 cm long, 2 cm wide, composed of many crowded staminal phalanges; each staminal phalange with column 4-9 mm x 1.5-2.5 mm, compressed to flat, containing 3-6 stamens with very short filaments, 0.5-1.5 mm x 0.4-0.6 mm and oblong anthers, 2.5 mm long.

Sedative (leaves)

PROSEA (Plant Resources of South-East Asia) Foundation