灰干苏铁 hui gan su tie

Cycas pectinata Buchanan-Hamilton f. hongheensis (S. Y. Yang & S. L. Yang ex D. Y. Wang) Z. T. Guan.

Trunk cylindric, sometimes branched, to 8 m × 60 cm, apex not tomentose; bark gray, smooth toward base of trunk, with fine, longitudinal fissures. Leaves 20-50(-60), 1-pinnate, 50-120 × 15-35 cm; petiole subterete, 10-25 cm, with 25-50 spines along each side; leaf blade oblong to elliptic-lanceolate, strongly "V"-shaped in cross section, recurved, pale brown tomentose when young; leaflets in 50-70 pairs, horizontally inserted at 45-50° above middle of rachis, glaucous when mature, 8-18 cm × 6-8 mm, leathery, densely pubescent when young, midvein flat adaxially when fresh (but sulcate when dry), prominent abaxially, base decurrent, margin ± revolute, apex

acuminate, pungent. Cataphylls lanceolate, 3-5 × 1-1.5 cm, densely pale brown tomentose adaxially, apex acuminate, pungent. Pollen cones and megasporophylls unknown.

* Dry and hot, sunny forests with sparse trees on sharp limestone slopes; 400-600 m. SE Yunnan (Gejiu Shi).

Very rapidly disappearing in the wild as a result of over collec-tion by commercial dealers and habitat destruction; it should be con-sidered an endangered species in China. There is no doubt as to the distinctiveness of this species on the basis of vegetative characters, although its affinities are difficult to ascertain in the absence of fertile material.