Etymology: from Latin falcatus, falcate or curved in a sickle-shape, from the distinctively curved leaflets. Historical notes: Distinguishing features: the spongy endocarp place this species in the Cycas rumphii Miq. group (subsection Rumphiae, Hill 1994), although it differs markedly in many other respects. The small seeds are not typical of this group, and neither are the distinct long lateral spines on the megasporophyll lamina or the narrow, falcate leaflets. The similar C. riuminiana from the Philippines is distinguished by shorter leaves and longer, harder cataphylls. C. falcata also has falcate, keeled leaflets with distinctly recurved margins and the midrib not raised above. Distribution and habitat: Cycas falcata is known from two localities on the main island of Sulawesi and from Kabaena Island off the south-eastern coast of Sulawesi. It occurs in habitats ranging from closed forest to open short tree savanna with grasses dominant, in full sun to heavy shade, over limestone or serpentinite substrates. The habitat of this species is quite different to the habitats of other species in the C. rumphii group, which generally occur in near-coastal situations (Hill 1994). Aquatic dispersal and the consequent coastal distribution are general features of this group. The departure of this species from the general state can be best regarded as an evolutionary advance, represented by the colonisation of a new and different site. Although many cycads are either calciphile or serpentiniphile (Hill 1996, 1998), such habitat preference can be seen from this example to be derived rather than ancestral conditions, and advances that have arisen independently on more than one occasion. The deeply dentate or shortly pectinate megasporophyll is another feature not common in subsection Rumphiae. Similar megasporophylls occur in the forest species C. macrocarpa Griff. from Thailand and peninsular Malaysia, but this species lacks the spongy endocarp and possesses a fibrous sarcotesta not evident in subsection Rumphiae. Conservation status: Although probably not immediately threatened, this species is of apparently limited distribution and potentially vulnerable in the longer term. On the basis of a preliminary evaluation, the appropriate IUCN Red List category would be Lower Risk least concern (IUCN, 1994). Further field study is required to fully assess the conservation status of this species and indeed of most Asian cycad species. Description:
Stems arborescent, to 5 m tall, 12-30 cm diam. at narrowest point. Leaves deep green (olive green), highly glossy, 180-300 cm long, slightly keeled (opposing leaflets inserted at 150° on rachis), with 100-200 leaflets, tomentum shedding as leaf expands; terminated by a spine or paired leaflets; 3 mm long. Petiole 27-62 cm long (20-35% of total leaf), petiole glabrous, spinescent for 80-100% of length. Basal leaflets not gradually reducing to spines. Median leaflets simple, strongly discolorous, 170-300 mm long, 7.5-13 mm wide, inserted at 60-70° to rachis, decurrent for 5-7 mm, narrowed to 3-4 mm at base (to 45% of maximum width), 11-17 mm apart on rachis; median leaflets section slightly keeled, or strongly keeled; margins slightly recurved; apex acute, spinescent; midrib flat above, flat below or raised below (slightly). Cataphylls narrowly triangular, soft, pilose, 40-70 mm long. Megasporophylls 19-27 cm long, brown-tomentose; ovules 4-6, glabrous; lamina lanceolate (narrowly triangular), 60-70 mm long, 22-32 mm wide, shallowly pectinate, with 16-28 pungent lateral spines 7-12 mm long, 1 mm wide, apical spine distinct from lateral spines, 15-28 mm long, 2.5-4 mm wide at base. Seeds flattened-ovoid, 42-46 mm long, 25-30 mm wide; sarcotesta orange, not pruinose; fibrous layer absent; sclerotesta smooth, or apically crested (weakly). Spongy endocarp present.
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