6. Cycas revoluta Thunberg, Verh. Holl. Maatsch. Weetensch. Haarlem. 20(2): 424, 426-427. 1782.
苏铁 su tie
Trunk to 3(-8) m × 45(-95) cm, base and sometimes distal part with numerous adventitious lateral branches or bulbils, apex tomentose; bark gray-black, scaly. Leaves 40-100 or more, 1-pinnate, 0.7-1.4(-1.8) m × 20-25(-28) cm; petiole subtetragonal in cross section, 10-20 cm, with 6-18 spines along each side; leaf blade oblong- or elliptic-lanceolate, strongly "V"-shaped in cross section, recurved, brown tomentose when young; leaflets in 60-150 pairs, horizontally inserted at ca. 45° above rachis, not glaucous when mature, straight to subfalcate, 10-20 cm × 4-7 mm, leathery, sparsely pubescent abaxially, base decurrent, margin strongly recurved, apex acuminate, pungent. Cataphylls triangular, 4-5 × 1.5-2.3 cm, densely brown tomentose, apex acuminate. Pollen cones pale yellow, ovoid-cylindric, 30-60 × 8-15 cm; microsporophylls narrowly cuneate, 3.5-6 × 1.7-2.5 cm, apex rounded-truncate, cuspidate. Megasporophylls yellow to pale brown, 14-22 cm, densely tomentose; stalk 7-12 cm; sterile blade ovate to narrowly so, 6-11 × 4-7 cm, deeply laciniate, with 21-35 lobes 1-3 cm; ovules 2 or 3 on each side of stalk, densely pale brown tomentose. Seeds 2(-5), orange to red, obovoid or ellipsoid, somewhat compressed, (3-)4-5 × 2.5-3.5 cm, sparsely hairy; sclerotesta not grooved on sides. Pollination May-Jul, seed maturity Sep-Oct.
Thickets on hillsides on islands, sparse forests on mainland; 100-500 m. Fujian (Lianjiang Xian, Ningde Xian, and some islands) [S Japan (Kyushu, Ryukyu Islands)]
A vulnerable, if not endangered, species in China. Its formerly wide distribution in E Fujian has now been severely reduced as a result of over collection by commercial dealers and
habitat destruction. It was sporadically distributed in Fujian in the 1960s, but it is now uncertain that any wild populations still exist. Cycas revoluta is the most commonly cultivated
cycad because of its ornamental appearance, hardiness, and adaptability.