4. Cycas balansae Warburg, Monsunia. 1: 179. 1900.
宽叶苏铁 kuan ye su tie
Cycas chevalieri Leandri; ?C. micholitzii Dyer var. simplicipinna Smitinand; C. palmatifida Hung T. Chang & al.; ?C. parvula S. L. Yang ex D. Y. Wang; C. shiwandashanica Hung T. Chang & Y. C. Zhong; C. siamensis Miquel subsp. balansae (Warburg) Schuster; ?C. simplicipinna (Smitinand) K. D. Hill; ?C. tanqingii D. Y. Wang.
Trunk subterranean, to 40 × 35 cm above ground; bark dark brown, densely scaly. Leaves 5-20(-30), 1-pinnate, 1.5-3 m × 40-60 cm; petiole green in 1st year, 20-70 cm, subterete, with 10-25 spines 3-8 mm along each side, 2-6 cm apart; leaf blade oblong, flat; leaflets in 20-75 pairs, longitudinally inserted 1-3 cm apart at 60-100° to rachis, straight, 20-38 × (1.2-)1.8-2.5 cm, papery, base constricted into a very short petiolule, margin flat or somewhat undulate, apex long acuminate. Cataphylls triangular, 4-6 × 1.2-1.5 cm, brown tomentose. Pollen cones subcylindric, 15-25 × 4-7 cm; microsporophylls broadly cuneate, 1.4-1.7 cm × 7-10 mm, pale brown tomentose abaxially, apex of median microsporophylls shortly acute, blunt. Megasporophylls 5-15(-20), loosely grouped, 9-13 cm, pale brown tomentose, glabrescent; stalk 5-7 cm; sterile blade broadly ovate, subcordate, or rarely obovate, 3.5-5.5 × 2.5-5 cm, deeply divided into 15-25 subulate, pointed lobes 2-3.5 cm, terminal lobe somewhat flattened, 2.5-4 cm; ovules 2 or 3 on each side of distal part of stalk, glabrous. Seeds often 2, yellowish when fresh, brown when dry, broadly ovoid or ellipsoid, 1.8-2.7 × 1.5-2.5 cm; sclerotesta smooth. Pollination Mar-May, seed maturity Sep-Nov.
Lateritic soil in monsoon forests, deep sand on limestone-derived soil in forests; 100-800 m. S Guangxi (Fangcheng Gezu Zizhixian), S Yunnan [Laos, Myanmar, Thailand, Vietnam]
There are taxonomic problems with the species delimitation of Cycas balansae. For example, C. simplicipinna and the recently described C. parvula and C. tanqingii, here tentatively placed in synonymy, may merit recognition as distinct species. However, a meaningful evaluation cannot be made until more material has been studied, particularly of fertile specimens. Chinese plants of C. balansae have been misidentified as C. siamensis Miquel (e.g., in FRPS). The latter species occurs only in Cambodia, Laos, Malaysia, Myanmar, Thailand, and Vietnam.