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Cycas segmentifida D. Y. Wang & C. Y. Deng

叉孢苏铁

Description from Flora of China

Cycas acuminatissima Hung T. Chang & al.; C. longiconifera Hung T. Chang & al.; C. longlinensis Hung T. Chang & Y. C. Zhong; C. multifida Hung T. Chang & Y. C. Zhong; C. xilingensis Hung T. Chang & Y. C. Zhong.

Trunk subterranean, to 70 × 70 cm above ground; bark dark brown, densely scaly. Leaves 15-25, 1-pinnate, 2-3.3 m × 45-60 cm; petiole blue in 1st year, later green, 0.6-1.5 m, subterete, with 25-55 spines (1-)2-3.5 mm along each side, 1-2.5 cm apart; leaf blade oblong, flat, pale brown tomentose when young; leaflets in 55-110 pairs, longitudinally inserted 1-1.8 cm apart at 75-90° to rachis, straight, 21-40 × 1.2-1.8 cm, leathery, glabrous abaxially, midvein raised on both surfaces only when fresh, flat abaxially when dry, base decurrent, margin flat or somewhat undulate, apex attenuate, pungent. Cataphylls triangular, 7-9 × 1.5-2.5 cm, densely pale brown tomentose, apex long, somewhat soft. Pollen cones yellow, narrowly ellipsoid-cylindric, 30-60 × 5-12 cm; microsporophylls narrowly cuneate, 2-2.5 × 1-1.2 cm, apex with short, upcurved mucro or nearly blunt. Megasporophylls 25-50, densely grouped, 10-16(-20) cm, pale brown tomentose; stalk 6-9(-13) cm, yellowish brown tomentose; sterile blade ovate, broadly ovate, or cordate-ovate, 5-9 × 4-8(-11) cm, margin glabrescent and pectinate, with 33-45 sometimes forked lobes 1.5-7 cm, terminal lobe subulate to rhombic-lanceolate, 2-7 cm × 2-8 mm, margin usually irregularly serrulate; ovules (1 or)2 or 3 on each side of distal part of stalk, glabrous. Seeds (2 or)3-5, pale yellowish, globose or broadly obovoid, slightly compressed, 2.8-3.5 × 2.6-3 cm, base contracted into point; sclerotesta finely verrucose. Pollination Mar-Jun, seed maturity Nov-Dec.

Differs from Cycas szechuanensis in its subterranean trunk, blue young petioles, and wider leaflets. As defined here, C. segmentifida is close to C. balansae, but is a wide-ranging, more northern species, differing in its blue young petioles, with much shorter spines, and its more numerous megasporophylls (30-50 together), with more lobes on the sterile blade.

* Lateritic soil derived from sandstone in semishade of broad-leaved or mixed forests; 600-900 m. S Guizhou, W Guangxi, SE Yunnan (Funing Xian)

裸子植物区 Gymnosperm Area


 

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