1. Cycadaceae (苏铁科)
2. Cycas (苏铁属)
3. Cycas hainanensis (海南苏铁)

Trunk to 1.5(-2.5) m × ca. 40 cm, inflated toward base; bark dark gray and scaly toward apex of trunk, white-gray and nearly smooth toward base. Leaves 50-80, 1-pinnate, 1-2.2 m × 30-50 cm; petiole rhombic in cross section, 20-70 cm, with 50-80 spines along each side from base upward; leaf blade elliptic-oblong, flat; leaflets in 50-80 pairs, longitudinally inserted 0.8-1.5 cm apart at 40-50° to rachis, straight, 15-30 cm × 6-9(-11) mm, leathery, glabrous abaxially, base decurrent, margin flat or slightly recurved, apex acuminate, pungent. Cataphylls triangular, 5-5.5 × 2-2.3 cm, densely brown tomentose, apex abruptly tapered into a long point, soft and recurved when fresh, becoming hard and straight when dry. Pollen cones unknown. Megasporophylls more than 30, tightly grouped, 14-20 cm, brown tomentose; stalk 7-12 cm; sterile blade greenish, ovate or broadly so, 6.5-9 × 6-9(-12) cm, glabrescent, margin pectinate, with 13-27 lobes 1-3 cm, terminal lobe flattened, oblong or triangular, 2-3(-4) × 0.7-2(-3) cm, remotely serrulate; ovules 1 or 2 on each side of distal part of stalk, glabrous. Seeds greenish to yellowish, broadly ovoid or subglobose, slightly compressed, 3.5-4.5 × 2.8-3.6 cm; sclerotesta finely verrucose. Pollination Mar-May, seed maturity Sep-Oct.

* Tropical jungles and thickets with sparse trees; 100-1000 m. Hainan