|Photo Ken Hill
|The Cycad Pages
- Cycas silvestris K.D. Hill, "Telopea 5(1): 181-182, fig. 1" (1992). H - NSW
- "TYPE: Australia, Queensland, c. 0.75 km NW of Bolt Head, J. Clarkson 8813 & J. Neldner, 14 July 1990 (holo NSW; iso BRI, MBA)."[NSW][NSW][NSW][NSW][NSW][NSW]
From the Latin silvestris, `of the forests', in reference
to the closed forest habitat.
|Photo Ken Hill
Hill 1992, fig. 1.
Historical notes: This species was discovered only in 1986 and named in 1992.
Distinguished from other Australian species by the broader and
relatively thinner adult leaflets. A striking qualitative distinction
is the smooth trunk, resulting from the
shedding of leaf bases and cataphylls more than about 4 years
old. These organs are retained throughout in C. media and
other related species.
The broad, falcate leaflets and the non-pectinate megasporophyll
apex with a distinct apical spine are similar to those of the
complex surrounding C. rumphii Miq., which comprises about
12 taxa ranging from Sri Lanka and East Africa
to Fiji and Tonga. Seeds, however, lack the spongy layer present
in the C. rumphii complex (Dehgan & Yuen 1983,
C. silvestris also differs from superficially similar
taxa on South Pacific Islands (C. seemannii A. Br.) in
the strongly spinose petiole (the Pacific Island plants have no
or rarely few spines on petioles) and the markedly smaller seeds.
Two taxa in the C. rumphii group are known from Papua
New Guinea (Hill 1994), all of which differ from C. silvestris
in the large seeds with spongy endocarp. Early reports of C.
rumphii from Queensland refer to C. silvestris (Bailey
Distribution and habitat:
C. silvestris is known only from subcoastal forests near
the north-eastern tip of Cape York Peninsula, near Temple Bay
and to the north and south of the Olive River estuary. These quite
rich and complex rainforests and Melaleuca-dominated forests
occur on white siliceous sands from old beach-dunes, and this cycad
appears to be endemic to that substrate.
This taxon is known from a few small stands that are not
1997 IUCN Red List of Threatened Plants category V.
ROTAP category 2V-.
|Photo Ken Hill
Stems arborescent, to 3(-4) m tall, 10-15 cm diam. at narrowest point.
Leaves bright green or deep green, highly glossy, 100-200 cm long, flat (not keeled) in section (opposing leaflets inserted at 180° on rachis), with 90-200 leaflets, with orange tomentum shedding as leaf expands; terminated by paired leaflets or a spine 1.5-10 mm long. Petiole 30-50 cm long (15-25% of total leaf), petiole glabrous, spinescent for 10-90% of length. Basal leaflets not gradually reducing to spines, 170-340 mm long.
Median leaflets simple, strongly discolorous, 150-370 mm long, 9-15 mm wide, inserted at 45-60° to rachis, decurrent for 5-10 mm, narrowed to 3.5-5 mm at base (to 25-40% of maximum width), 11-17 mm apart on rachis; median leaflets section flat; margins slightly recurved; apex aristate, not spinescent; midrib flat above, raised below.
Cataphylls linear, pungent, 130 mm long, articulated.
Pollen cones narrowly ovoid, orange to brown, 11-22 cm long, 5-7 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 20-25 mm long, 11-13 mm wide, fertile zone 16-18 mm long, sterile apex 4-6 mm long, level, apical spine prominent, sharply upturned, 5-15 mm long.
Megasporophylls 25-38 cm long, brown-tomentose; ovules 2-10, glabrous; lamina lanceolate, 30-85 mm long, 15-45 mm wide, regularly dentate, with 20-36 pungent lateral spines 2-4 mm long, 1-2 mm wide, apical spine distinct from lateral spines, 8-26 mm long.
Seeds flattened-ovoid, 30-35 mm long, 25-30 mm wide; sarcotesta orange-brown, not pruinose, 1.5-2 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.