Photo Ken Hill
logo
The Cycad Pages
Cycas litoralis


Etymology: From the Latin, litoralis, of the sea-shore, in reference to the habitat of this species.

Literature: Kurz 1877 (as C. rumphii), Backer 1925 (as C. rumphii p.p.), Ridley 1925 (as C. rumphii), Leandri 1931 (as C. rumphii), Ochse 1931 (as C. rumphii p.p.), Schuster 1932 (as C. rumphii), Kanehira 1938 (as C. rumphii p.p.), Ho & Duong 1960 (as C. rumphii), Suvatabandhu 1961 (as C. rumphii), Backer & Bakhuizen van den Brink 1963 (as C. rumphii p.p.), Smitinand 1971 (as C. rumphii), Smitinand 1972 (as C. rumphii).

Illustrations: Ridley 1925, Smitinand 1971, Cheng, Fu & Cheng 1975 (as C. rumphii).

Historical notes: recognised as a distinct taxon only in 1995, and formally described in 1999.

Distinguishing features: The non-pectinate megasporophyll and the large seed with spongy endocarp place this species unmistakably in the C. rumphii group. Within that group, it is distinguished from C. rumphii and all related species occurring to the south and east by the distinct, stout spines terminating the microsporophylls. C. thouarsii from the south-western Indian Ocean shares the microsporophyll character, but differs in having narrower leaflets that are distinctly glaucous when developing. C. zeylanica from Sri Lanka and The Andamans is characterised by longer, narrower and more attenuate megasporophylls, more widely spaced leaflets and more abundant, longer and distinctly pungent cataphylls with a more rufous tomentum. C. edentata from the Philipppines possesses an even longer and more attenuate microsporophyll apex, with shorter and broader pollen cones. Distinction from C. macrocarpa is discussed under the latter.

Distribution and habitat: C. litoralis occurs in south Vietnam, southern Burma and southern Thailand, extending south into peninsular Malaysia and Sumatra, but apparently not elsewhere in Indonesia or Malaysia. Once common around the coast of southern Thailand, but now removed from many sites. A stand still exists in a reserve on the headland at Ao Manao Nowl, a few km S of Narathiwat and just north of the Taksin Summer Palace. Cultivated plants seen in different places had reportedly come from Chumphon and Phuket, with other records from Ko Kut. This species occurs only along shorelines, in full sun to moderate shade in often dry littoral scrubs on beach sand or rocky headlands, often in very shallow soil and apparently over both granite and limestone substrates.

Conservation status: Once abundant and widespread, this species occurred in coastal sites that have experienced severe pressures from population increase and development. Although probably not immediately threatened, it is potentially vulnerable in the longer term. IUCN (1994) Red List status VU ?.
Photo Ken Hill
Photo Ken Hill

Description:

Stems arborescent, to 3(-10) m tall, 11-20 cm diam. at narrowest point.

Leaves bright green, highly glossy, 150-230 cm long, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with 100-170 leaflets, tomentum shedding as leaf expands; rachis consistently terminated by paired leaflets. Petiole 50-90 cm long (30-50% of total leaf), petiole glabrous, spinescent for 5-60% of length. Basal leaflets not gradually reducing to spines, 170-260 mm long.

Median leaflets simple, strongly discolorous, 260-350 mm long, 14-19 mm wide, inserted at 65-80° to rachis, decurrent for 8-13 mm, narrowed to 6-8 mm at base (to 35-50% of maximum width), 15-35 mm apart on rachis; median leaflets section flat; margins slightly recurved; apex acute, not spinescent; midrib flat above, raised below.

Cataphylls narrowly triangular, soft, pilose, persistent.

Pollen cones narrowly ovoid, orange, 35-45 cm long, 13-17 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 38 mm long, 21 mm wide, fertile zone 29 mm long, sterile apex 9 mm long, level, apical spine prominent, sharply upturned, 24 mm long.

Megasporophylls 30-50 cm long, white-tomentose or yellow-tomentose; ovules 4-8, glabrous; lamina lanceolate, 90-120 mm long, 25-40 mm wide, obscurely dentate or regularly dentate, with 6-14 soft lateral spines 0-1 mm long, 0-1 mm wide, apical spine distinct from lateral spines, 25-40 mm long, 5-8 mm wide at base.

Seeds flattened-ovoid, 52 mm long, 43 mm wide; sarcotesta orange-brown, not pruinose, 4 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp present.


The Cycad Pages

© 1998-2012 Royal Botanic Gardens Sydney
Written and maintained by Ken Hill 1998-2010
Maintained by Leonie Stanberg and Dennis Stevenson 2010-2012
This site is currently not being maintained