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The Cycad Pages
Cycas javana

Cycas javana (Miq.) de Laub., "in D.Y. Wang, Cycads in China: 65" (1996). H—L


Etymology: From the island of Java, with the Latin suffix -ana, a connection, referring to its occurrence on and initial collection from Java.

Historical notes: Described in 1842 as a variety of C. circinalis by Dutch botanist Miquel. Miquel later subsumed this variety into C. rumphii, and no further note was made of it until it was raised to specific status in 1996 by de Laubenfels (in Wang, 1996).

Distinguishing features: The long, narrowly triangular megasporophyll apex with numerous distinct slender lateral spines separate this species from otherwise similar forest species from Malaysia (C. macrocarpa and eastern Indonesia (C. scratchleyana).

Distribution and habitat: Primarily a Javan species, extending to southern Sumatra and possibly the western Sunda Islands, occurring in closed forest on slopes and ridges from low to middle elevations, mostly on volcanic soils.

Conservation status: Much of the primary forest habitat has been cleared or degraded in recent decades, and the habitat loss continues today. This species is poorly known but apparently under considerable threat. IUCN (1994) Red List status DD/EN?.

Description:

Stems arborescent.

Leaves bright green, highly glossy, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with brown tomentum shedding as leaf expands; terminated by a spine or paired leaflets; 6 mm long. Petiole 40-60 cm long, glabrous, spinescent for 40-90% of length. Basal leaflets not gradually reducing to spines.

Median leaflets simple, strongly discolorous, 240-370 mm long, 10-15 mm wide, narrowed to 2.5-6 mm at base (to 20-35% of maximum width); median leaflets section flat; margins slightly recurved; apex acute, not spinescent; midrib raised above, raised below.

Cataphylls linear, soft, pilose, articulated.

Pollen cones fusiform; microsporophyll lamina firm, not dorsiventrally thickened, apical spine prominent, sharply upturned.

Megasporophylls 24-36 cm long; ovules 2-6, glabrous; lamina lanceolate, 60-95 mm long, 11-21 mm wide, regularly dentate, with 12-30 pungent lateral spines 1-2 mm long, 1 mm wide, apical spine distinct from lateral spines, 10-30 mm long, 1.5-3 mm wide at base.

Seeds ovoid; fibrous layer absent; sclerotesta smooth. Spongy endocarp present.


The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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