Etymology: From the latin sex, six, and seminifera, seed-bearing, in the misplaced belief that the six seeds observed on the megasporophyll of the type plant was a diagnostic distinction. Literature: Wang 1996, as C. miquelii. Illustrations: Wang 1996, as C. miquelii. Historical notes: Metcalf (1942) applied the name C. inermis to this species. Later treatments from China (Cheng et al. 1975, Zhou et al. 1990) also confused it with C. pectinata (which does occur in China, but considerably to the west of this species). Occurrences in Vietnam were overlooked by Ho (1960, 1991) and Hiep & Vidal (1996). More recently, treatments of Chinses species by Wang (1996) and Chen and Stevenson (1998) have misapplied the name C. miquelii to this species. Distinguishing features: This species is most readily distinguished by the dwarf habit with a short stem and short, flat leaves with short, narrow, flat, rather stiff and pungent leaflets, and the small but broad megasporophyll lamina with a broad apical spine distinct from the lateral spines. Petioles are often unarmed (hence the misapplication of the epithet "inermis"), but this character is not at all consistent. Distribution and habitat: Widespread in southern and central Guangxi province of China, and in Cao Bang province in central northern Vietnam in the border region with Guangxi, with a disjunct occurrence in Thanh Hoa province south of Hanoi. Locally abundant, growing in crevices in bare outcrops in rugged karst limestone country, often on vertical faces with no visible soil. Conservation status: Although there is a clear demand for this species in horticultural markets in China and Vietnam, and a substantial collection from the wild for this trade, this species is extremely abundant in many inaccessible sites and is not considered to be at risk. IUCN (1994) Red List status LR nt.
Description:
Stems arborescent or acaulescent, to 0-0.6 m tall, 6-15 cm diam. at narrowest point; 5-30 leaves in crown. Leaves deep green or grey-green, semiglossy, 50-110 cm long, slightly keeled or flat (not keeled) in section (opposing leaflets inserted at 150-180° on rachis), with 60-130 leaflets, with brown tomentum shedding as leaf expands; rachis consistently terminated by paired leaflets. Petiole 12-40 cm long (20-35% of total leaf), petiole glabrous, unarmed or spinescent for 5-80% of length. Basal leaflets not gradually reducing to spines, 40-110 mm long. Median leaflets simple, strongly discolorous, 70-260 mm long, 6-13 mm wide, inserted at 60-85° to rachis, decurrent for 2-5 mm, narrowed to 2-6 mm at base (to 30-60% of maximum width), 6-17 mm apart on rachis; median leaflets section slightly keeled; margins flat, or slightly recurved; apex aristate, spinescent; midrib raised above, raised below. Cataphylls narrowly triangular, pungent or soft, thinly sericeous or lacking tomentum or pilose, 40-90 mm long, persistent. Pollen cones narrowly ovoid to fusiform, orange, 12-26 cm long, 5-7 cm diam.; microsporophyll lamina soft, not dorsiventrally thickened, 20-30 mm long, 10-20 mm wide, fertile zone 18-27 mm long, sterile apex 2-4 mm long, raised, apical spine rudimentary or absent, sharply upturned, 0-3 mm long. Megasporophylls 9-12 cm long, brown-tomentose; ovules 2-6, glabrous; lamina orbicular, 60-90 mm long, 35-45 mm wide, deeply pectinate, with 28-40 soft lateral spines 30-40 mm long, 1.5-2.5 mm wide, apical spine distinct from lateral spines, 30-40 mm long, 5-12 mm wide at base. Seeds ovoid, 18-25 mm long, 18-22 mm wide; sarcotesta yellow, not pruinose, 1-2 mm thick; fibrous layer absent; sclerotesta smooth to verrucose. Spongy endocarp absent.
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