Etymology: From Changjiang county in western Hainan province, with the Latin termination -ensis, place of origin. Historical notes: Described in 1998 by Chinese botanist N. Liu. Distinguishing features: C. changjiangensis is allied to C. hainanensis, differing in the dwarf, largely subterranean habit and the smaller megasporophyll lamina and smaller seeds. Distribution and habitat: Known only from western Hainan Island. This species grows in seasonally dry woodlands on deeper sandy soils on flatter country. Conservation status: Some quite large populations still exist in the wild, the natural habitat not being good agricultural land. Other populations are severely degraded, and the overall reduction in recent years indicates that this species should be regarded as threatened. 1997 IUCN Red List of Threatened Plants category V.
Description:
Stems arborescent, to 0.3-1.5(-2.5) m tall, 20 cm diam. at narrowest point; 30-60 leaves in crown. Leaves bright green, highly glossy, 70-230 cm long, moderately keeled (opposing leaflets inserted at 120-160° on rachis), with 80-220 leaflets, with orange tomentum shedding as leaf expands; rachis usually terminated by paired leaflets. Petiole 20-70 cm long (20-30% of total leaf), petiole glabrous, spinescent for 70-100% of length. Basal leaflets not gradually reducing to spines, 70-140 mm long. Median leaflets simple, strongly discolorous, 150-300 mm long, 6-10 mm wide, inserted at 40-70° to rachis, decurrent for 2-7 mm, narrowed to 2.5-3 mm at base (to 30-45% of maximum width), 8-15 mm apart on rachis; median leaflets section slightly keeled; margins slightly recurved; apex acute, spinescent; midrib raised above, raised below (less prominently). Cataphylls narrowly triangular, soft, pilose, 50-90 mm long, persistent. Pollen cones fusiform; microsporophyll lamina soft, not dorsiventrally thickened, apical spine absent. Megasporophylls 16-17 cm long, brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 70-110 mm long, 40-60 mm wide, deeply pectinate, with 15-32 soft lateral spines 25-32 mm long, 2 mm wide, apical spine distinct from lateral spines, 20-30 mm long, 10-25 mm wide at base. Seeds subglobose to ovoid, 35-40 mm long, 30-35 mm wide; sarcotesta yellow, not pruinose, 2 mm thick; fibrous layer absent; sclerotesta verrucose. Spongy endocarp absent.
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