Description from Flora of China
Cycas circinalis Linnaeus var. pectinata (Griffith) Schuster; C. dilatata Griffith; C. jenkinsiana Griffith; C. pectinata Griffith; C. wallichii Miquel.
Trunk cylindric, often dichotomously branched toward apex and gradually thickened toward base, up to 16 m × 60 (-90) cm, apex not tomentose; bark gray or white-gray, smooth toward base of trunk. Leaves 40-80(-100), 1-pinnate, 0.7-1.2 (-1.5) m × 20-30(-40) cm; petiole compressed orbicular in cross section, 10-35 cm, with 6-15 spines along each side above middle part; leaf blade oblong-lanceolate, flat or occasionally slightly "V"-shaped in cross section, pale brown tomentose when young; leaflets in 50-100 pairs, longitudinally inserted at 50-60° to rachis, straight to falcate, 9-20 cm × 5-7 mm, thickly, leathery, midvein flat adaxially, sulcate when dry, raised abaxially, base decurrent, margin slightly recurved, apex acute, pungent. Cataphylls triangular, 3.5-4.5 × 1.5-2 cm, brown tomentose, apex soft. Pollen cones fusiform, 30-45 × 10-15 cm; microsporophylls cuneate, 3.5-5 × 1.2-2.5 cm, densely pale brown tomentose, apex thickened, with an upcurved point 3-4 cm. Megasporophylls more than 30, tightly grouped, 13-18 cm, densely yellowish brown silky hairy; stalk 4-7 cm; sterile blade deltoid-ovate or suborbicular, 7-9 × 6-10 cm, margin pectinate, with 29-37 lobes 2.5-3.5 cm, terminal lobe subulate, 3-4.5 cm; ovules 1(-3) on each side of distal part of stalk, glabrous. Seeds 2(-4), orange, becoming dark brown, often obovoid, compressed, 4.5-6 × 4-4.7 cm; sclerotesta smooth, sarcotesta with a mixed, thick, fleshy, fibrous layer. Pollination Jun-Jul, seed maturity Feb-Mar.
A vulnerable species in China. Cultivated as an ornamental in S Yunnan and elsewhere in SE Asia. Chinese plants have been misidentified as C. rumphii Miquel (e.g., in FRPS), which occurs only in Indonesia and Papua New Guinea.
Dry, open thickets in limestone mountains, red soil in sparse monsoon forests; 1000-1800 m. S Yunnan [Bangladesh, Bhutan, Cambodia, NE India, Laos, Myanmar, Nepal, Sikkim, Thailand, Vietnam]