Literature: Hill 1995b Illustrations: Griffith 1854. Historical notes: C. macrocarpa was described by William Griffith (1810--1845), a British colonial physician with the East India Company, and later botanist and superintendent of the Calcutta Botanic Gardens. He noted that the specimen was collected by Dutchman J.B. Westerhout, Assistant Resident of Malacca, in September 1842. Griffith did not publish his notes and drawings while living, and his work was bequeathed to the East India Company. It was compiled by John McLelland and published by the colonial government of Bengal in Calcutta in 1854, and included an illustration Griffith made while at the Calcutta Botanic Gardens. Although there was nothing to indicate that the illustration belonged to the description of C. macrocarpa, the compiler added a note to suggest that this may be the case, and it clearly matches the description and the specimen at Kew. This publication was fully technically correct, but it was ignored by all contemporaneous and subsequent cycad students. Foremost student of the Cycadales of that era, F.A.W. Miquel, overlooked the publication of the name C. macrocarpa until 1868, where he briefly mentioned it as a species unknown to him and doubtfully distinct. Alphonse de Candolle and his father collated, partly wrote and published a complete account of the known flora of the world over the period 1824--1876. He treated the cycads in 1868, including the name C. macrocarpa as a doubtful species, and noting that it was not known to him. In the Kew herbarium, the specimens collected by Westerhout were labelled C. rumphii and left at that. Hooker and Jackson in 1893 placed C. macrocarpa into the synonymy of C. rumphii in `Index Kewensis', a monumental publication endeavouring to list all published plant names and synonymies from the time of Linnaeus until 1885. There it has remained until now. Although apparently fairly common in the ridge forests of southern Thailand and Peninsular Malaysia, C. macrocarpa has been rarely collected. Henry Ridley (director of Singapore Botanic Gardens, 1901--1912) published the Flora of the Malay Peninsula between 1922 and 1925, in which he noted `hill forest forms of C. rumphii may be different'. Tem Smitinand later recognised the presence of 2 distinct taxa in southern Thailand in his treatment of Cycas for the Flora of Thailand. He correctly treated one as C. rumphii, but wrongly applied the name C. circinalis to the plants we now know to be C. macrocarpa. A photograph in habitat was published in `Nature Malaysiana' as C. sp. Taman Negara (vol. 17, p. 47, 1992). Distinguishing features: Distinguished by the long, pungent, narrowly triangular cataphylls with thick, woolly, rusty red-brown indumentum, the distinctly blue new growth. Leaflets are dark green when mature, narrow-based (2--4 mm wide at the base), with a narrow, raised, green midrib above. Distribution and habitat: These cycads originally occurred in primary closed forest (rainforest), on well-drained, often sloping, deep sandy clay-loam soils, and are said to still occur on the less disturbed ridges in southern Thailand and northern Malaysia. Conservation status: This species has suffered extensive habitat reduction that is ongoing, and must be regarded as vulnerable IUCN (1994) Red List status VU A2c.
Description:
Stems arborescent, to 12 m tall. Leaves deep green, highly glossy, 220-320 cm long, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with 160-220 leaflets, orange to brown, tomentum shedding as leaf expands; rachis usually terminated by paired leaflets. Petiole 40-70 cm long (15-25% of total leaf), petiole glabrous, spinescent for 80-100% of length. Basal leaflets not gradually reducing to spines, 150-250 mm long. Median leaflets simple, strongly discolorous, 240-450 mm long, 12-18 mm wide, inserted at 60-85° to rachis, decurrent for 5-12 mm, narrowed to 3-4 mm at base (to 15-30% of maximum width), 15-35 mm apart on rachis; median leaflets section flat; margins flat to slightly recurved; apex acute, not spinescent; midrib raised above, raised below. Cataphylls linear, pungent, pilose, 70-170 mm long, persistent. Pollen cones ovoid, orange, 16-22 cm long, 9-12 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 24-50 mm long, 14-20 mm wide, fertile zone 18-44 mm long, sterile apex 5-6 mm long, level, apical spine prominent to rudimentary, sharply upturned, 9-28 mm long. Megasporophylls 10-33 cm long, brown-tomentose; ovules 2-4, glabrous; lamina lanceolate, 50-100 mm long, 17-45 mm wide, shallowly pectinate, with 10-22 pungent lateral spines 5-18 mm long, 1-2.5 mm wide, apical spine distinct from lateral spines, 17-60 mm long, 2-7 mm wide at base. Seeds oblong, 45-65 mm long, 35-45 mm wide; sarcotesta yellow, not pruinose or slightly pruinose, 3-5 mm thick; fibrous layer present; sclerotesta smooth. Spongy endocarp absent.
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