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The Cycad Pages
Cycas elongata

Cycas elongata (Leandri) D.Yue Wang), "Cycads in China: 51, as C. elonga" (1996). L—P


Etymology: From the Latin elongatus, elongated, in reference to the elongated apical spine on the megasporophyll (although this is not a constant character in this species).

Literature: Wang 1996.

Illustrations: Wang 1996

Historical notes: Described in 1931 as variety of the closely related C. pectinata by French botanist Leandri (see C. chevalieri).

Distinguishing features: although Leandri distinguished the variety on the basis of the elongate apical spine on the megasporophyll, this character is not consistent throughout the population. C. elongata is closely allied to C. pectinata, but readily distinguished by the short leaves with short petioles and broad flat leaflets, the smaller and narrower male cones with shorter apical spines on the microsporophylls, and the overall smaller and narrower megasporophylls. The short, mostly spinescent petioles also distinguish C. elongata from C. clivicola and C. condaoensis. Male cones of C. elongata are also larger than those of the latter two species, with longer microsporophylls.

Distribution and habitat: Coastal hills in southern Vietnam, from Nha Trang north to Quang Ngai, Khanh Hoa, Phu Yen and Binh Dinh provinces. Locally abundant in forests to open shrublands on slopes, on dry gritty soil derived from coarse siliceous granite.

Conservation status: Although habitat is being reduced and a significant trade occurs in this species, it is not considered to be at risk in the short term. IUCN (1994) Red List status VU A2c.
Photo Ken Hill

Description:

Stems arborescent, to 2-5 m tall, 10-20 cm diam. at narrowest point; 30-60 leaves in crown.

Leaves bright green or grey-green, semiglossy, 90-140 cm long, moderately keeled (opposing leaflets inserted at 90-150° on rachis), with 130-240 leaflets, with white tomentum shedding as leaf expands; terminated by a spine or paired leaflets. Petiole 20-40 cm long (20-30% of total leaf), petiole glabrous, spinescent for 60-100% of length. Basal leaflets not gradually reducing to spines, 45-60 mm long.

Median leaflets simple, strongly discolorous, 140-220 mm long, 8-11 mm wide, inserted at 50-60° to rachis, decurrent for 3-5 mm, narrowed to 2.5-4.5 mm at base (to 30-40% of maximum width), 10-18 mm apart on rachis; median leaflets section flat; margins flat; apex acute, not spinescent; midrib raised above, raised below.

Cataphylls narrowly triangular, soft, thinly sericeous or lacking tomentum, 60-90 mm long, articulated.

Pollen cones narrowly ovoid, orange or brown, 25-35 cm long, 9-13 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened.

Megasporophylls 20-27 cm long, grey-tomentose or brown-tomentose; ovules 2-6, glabrous; lamina orbicular or ovate, 130-180 mm long, 50-70 mm wide, deeply or shallowly pectinate, with 36-38 soft lateral spines 20-25 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 30-55 mm long, 4-5 mm wide at base.

Seeds flattened-ovoid, 40 mm long, 30 mm wide; sarcotesta yellow; fibrous layer present; sclerotesta smooth. Spongy endocarp absent.


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Written and maintained by Ken Hill 1998-2010
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