|Photo Ken Hill
|The Cycad Pages
- Cycas pectinata Buch.-Ham., "Mem. Wern. Nat. Hist. Soc. 5(2): 322-323, figs 3, 5" (1826).
- TYPE: not known.
Cycas pectinata Griff., Not. Pl. Asiat. 4: 10 (1854).
- "TYPE: Icones Plantarum Asiatarum 4: Plate 360, Fig. 3, 1854."
Latin pectina, a comb, in reference to the long, comb-like
teeth of the megasporophylls.
Ho & Duong 1960,
Raizada & Sahni 1960,
Grierson & Long 1983,
Tang et al. 1997,
Hill & Yang 1999.
Cheng, Fu & Cheng 1975,
Grierson & Long 1983, Wang 1996, Hill & Yang 1999.
Cycas pectinata was the fourth species of Cycas to be named,
described in 1826 by Scottish surgeon and botanist Francis
Buchanan-Hamilton (1762-1829), who worked as a surgeon
in the Bengal medical service (1795-1815) and was superintendent
of the Botanical Garden Calcutta (1814-1815). The type is not
known. No type was cited, but reference was made to occurrence
in "the hills which bound Bengal to the east", and the
description cited "Habitat in Camrupae orientalis sylvis".
Cycas angulata R. Brown and Olus calappoides of
Rumphius (C. rumphii) were cited (erroneously) in synonymy.
The name has been attributed to Griffith, although he did not
actually add his name to the binomial when describing it (Griffith's
practice apparently was to add his name to new binomials, and
place no name on existing or previously published binomials).
Zhou et al. (1990)
regarded Hamilton's publication as illegitimate
because C. angulata was cited as a synonym. The latter
was cited, but with a question mark, indicating that the author
was unsure of the placement of C. angulata. This does not
invalidate Hamilton's publication (see
Greuter et el. 1990,
Art. 63.1, note 1, example 6). The primary set of Hamilton's Bengal
collections eventually went to Wallich and thence to Kew (K-W).
A second set went to E. Neither set includes a specimen
that could be regarded as the type of C. pectinata.
the very large, ovoid male cones
with long, narrow microsporophylls, those with long apical spines,
readily distinguish this species from others in the C. pectinata
group. The group is distinguished by the broad, pectinate
megasporophylls and the fibrous layer within the sarcotesta.
Distribution and habitat:
Cycas pectinata is abundant
in the hill forests of north-eastern India, and has also been
collected from Nepal and Bhutan. It extends into northern Burma
and Yunnan Province in southern China, and south and east into
northern Thailand, Laos and Vietnam. This species occurs in medium
to tall closed forest on deep, often clay-rich and more fertile soils,
usually as part of the general shrub understorey in moderate to
deep shade. C. pectinata is a plant of medium to higher
elevations and moist conditions. It is recorded from a variety
of substrates, but most frequently occurs on clay soils over limestone.
a widespread and locally abundant species.
Although its habitat is continually being reduced, large populations
remain, many in reserved areas in several different countries, and it
is not under any immediate threat of extinction.
IUCN (1994) Red List
status VU A2c (on the basis of the continuing population decline,
although the very large populations remaining indicate that the short-term
threat of extinction is low).
|Photo Ken Hill
|Photo Ken Hill
Stems arborescent, to 1-12 m tall, 14-20 cm diam. at narrowest point; 30-40 leaves in crown.
Leaves deep green or grey-green, semiglossy, 150-240 cm long, flat (not keeled) in section (opposing leaflets inserted at 170-180° on rachis), with 180-312 leaflets, with white tomentum shedding as leaf expands; rachis consistently terminated by a spine 1-46 mm long. Petiole 30-80 cm long (25-50% of total leaf), petiole glabrous, spinescent for 30-80% of length. Basal leaflets not gradually reducing to spines, 50-160 mm long.
Median leaflets simple, strongly discolorous, 200-315 mm long, 7.5-10.5 mm wide, inserted at 45-60° to rachis, decurrent for 4-8 mm, narrowed to 2.5-4 mm at base (to 35-45% of maximum width), 8-13 mm apart on rachis; median leaflets section flat; margins slightly recurved; apex acute, spinescent to not spinescent; midrib raised above, raised below.
Cataphylls narrowly triangular, soft, pilose, articulated.
Pollen cones ovoid, yellow or green, 30-55 cm long, 16-22 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 43-60 mm long, 19-24 mm wide, fertile zone 35-57 mm long, sterile apex 3-8 mm long, level, apical spine prominent, sharply upturned, 17-32 mm long.
Megasporophylls 22-30 cm long, grey-tomentose; ovules 2-4, glabrous; lamina orbicular, 110-180 mm long, 100-130 mm wide, deeply pectinate, with 40-50 soft lateral spines 26-75 mm long, 2-3 mm wide, apical spine distinct from lateral spines, 35-75 mm long, 5-12 mm wide at base.
Seeds flattened-ovoid, 42-45 mm long, 33-45 mm wide; sarcotesta yellow, not pruinose, 4-7 mm thick; fibrous layer present; sclerotesta smooth. Spongy endocarp absent.