|Photo Ken Hill
|The Cycad Pages
- Cycas pachypoda K.D. Hill, "Bot. Rev. 70(2): 176-178, fig. 13" (2004). H—HN
- "TYPE: Vietnam: Binh Thuan: Tuy Phong, Vinh Hao (11°20'22""N 108°51'17""E), 20 May 1998, Hill 5012 (holo HN, iso NSW, K, NY, PE, BKF, L, P, MO)."
From the Greek pachys, thick, and podos, foot,
referring to the distinctive broad base of the trunk of this species.
Although abundant cycad along the main north-south highway in southern
Vietnam, C. pachypoda was recognized as a distinct species
only in the late 1990's.
Cycas pachypoda is distinguished by the very broad and abruptly swollen base,
the thick, fissured and corky bark, the slightly keeled or flat leaves with
short petioles and stiff, narrow leaflets, the medium microsporangiate cones
with shorter apical spines on the microsporophylls, and the overall small
megasporophylls. C. siamensis is similar in the swollen base and thick bark,
but can be distinguished by the much smaller microsporangiate cones and the
flat leaves with more persistent tomentum and lower leaflets gradually reducing
to spines. The short, mostly spinescent petioles distinguish C. pachypoda
from . clivicola and C. condaoensis. Microsporangiate cones of C. pachypoda
are also larger than those of these two species, and have longer
Distribution and habitat:
Known only from a limited range of coastal hills in southern Vietnam, Bin
Thuan and Dong Nai provinces (Fig. 11). Locally abundant in dry open thorn
shrublands on rocky slopes, on dry gritty soil derived from coarse siliceous
granite. Original vegetation in much of this region was low monsoon woodland
and thorn scrub, although much of the original woodland has been cut for fuel.
Not considered to be at risk in the short term, but requiring study of
actual population extent.
IUCN (1994) Red List
|Photo Ken Hill
|Photo Ken Hill
Stems arborescent, to 0.5-1.5 m tall, 12-17 cm diam. at narrowest point; 50-80 leaves in crown.
Leaves deep green or grey-green, semiglossy, 90-130 cm long, slightly keeled or flat (not keeled) in section (opposing leaflets inserted at 150-170° on rachis), with 160-250 leaflets, with white tomentum shedding as leaf expands; rachis usually terminated by a spine 5-15 mm long. Petiole 10-20 cm long (10-20% of total leaf), petiole glabrous, spinescent for 80-100% of length. Basal leaflets not gradually reducing to spines, 15-45 mm long.
Median leaflets simple, strongly discolorous, 120-180 mm long, 6-7 mm wide, inserted at 50-60° to rachis, decurrent for 3-5 mm, narrowed to 2.5-3.5 mm at base (to 40-50% of maximum width), 6-12 mm apart on rachis; median leaflets section flat, or slightly keeled; margins flat, or slightly recurved; apex acute, spinescent; midrib raised above, raised below.
Cataphylls narrowly triangular, soft, thinly sericeous or lacking tomentum, 80-110 mm long, articulated.
Pollen cones narrowly ovoid, orange or brown, 25-40 cm long, 10-15 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 40-52 mm long, 17-20 mm wide, fertile zone 30-40 mm long, sterile apex 7-12 mm long, level, apical spine prominent, sharply upturned, 9-15 mm long.
Megasporophylls 7-15 cm long, brown-tomentose; ovules 2-4, glabrous; lamina orbicular, 90-120 mm long, 40-70 mm wide, deeply pectinate, with 30-36 soft lateral spines 10-20 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 15-40 mm long, 4-5 mm wide at base.
Seeds flattened-ovoid; sarcotesta yellow; fibrous layer present; sclerotesta smooth. Spongy endocarp absent.