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| The Cycad Pages
| | Cycas papuana
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- Cycas papuana F. Muell., Descr. Notes Papuan Pl. 4: 71-72 (1876).
- TYPE: New Guinea, Fly-River, D'Albertis s.n. (lecto (fide Hill 1994) MEL 68056; isolecto K).
Etymology:
From its original collection from the British Territory of Papua.
Illustrations:
Schuster 1932 (as
C. rumphii var. papuana).
Hill 1996, fig. 5.
Historical notes:
The basis of this species was cited only
as `On the Fly-River; D'Albertis.' The two sheets MEL68056 and
MEL68057 (photos NSW) apparently collected by D'Albertis were
annotated only by Mueller, and do not bear D'Albertis' name. A
portion of the former was sent to K by Mueller, according to his
annotation on the sheet. The sheet MEL 68056, annotated by Mueller
`parofolii supera / Fly-River', is more comprehensive, and has
been designated the lectotype.
Distinguishing features:
C. papuana is a member of the C. armstrongii group, differing
in the longer leaves with longer petioles and more leaflets (C.
armstrongii has leaves 55-90 cm long with petioles 10-25 long
and 160-220 leaflets). The long, unarmed petiole resembles that
of C. conferta, which differs in the somewhat shorter leaves
(70-110 cm long) with more closely crowded leaflets (spaced at 4.0-7.0
mm on rachis), less extended sterile apex on the microsporophylls
(6-8 mm long), and larger seeds (36-40 mm long). Both C. armstrongii
and C. conferta are endemic in the Northern Territory of
Australia.
Distribution and habitat:
Papua New Guinea, Western District, from the flood-plains of the
Fly River and around Daru west at least to the Bensbach River.
A sporadic but widespread component of savanna woodlands on flat
country, sometimes locally abundant.
Conservation status:
Abundant and apparently not at risk.
Description:
Stems arborescent, to 2.8 m tall. 30 leaves in crown.
Leaves bright green (bluish when new), semiglossy, 100-130 cm long, slightly keeled (opposing leaflets inserted at 130-160° on rachis), with 180-250 leaflets, with white and orange tomentum shedding as leaf expands; rachis usually terminated by a spine. Petiole 30-40 cm long (25-35% of total leaf), petiole glabrous, unarmed. Basal leaflets not gradually reducing to spines, 30-90 mm long.
Median leaflets simple, weakly discolorous, 80-130 mm long, 6-9 mm wide, inserted at 60-80° to rachis, decurrent for 1.5-5 mm, narrowed to 3.5-5.5 mm at base (to 55-65% of maximum width), 5.5-14 mm apart on rachis; median leaflets section flat; margins flat; apex acute, not spinescent; midrib raised above, raised below.
Cataphylls linear, pungent, pilose, persistent.
Pollen cones ovoid, orange, 15-20 cm long, 8-10 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 24 mm long, 10 mm wide, fertile zone 17 mm long, sterile apex 7 mm long, level, apical spine rudimentary, sharply upturned, 1-5 mm long.
Megasporophylls 16 cm long, brown-tomentose; ovules 4-6, glabrous; lamina lanceolate, regularly dentate, pungent, apical spine distinct from lateral spines.
Seeds ovoid, 32-35 mm long, 25-29 mm wide; sarcotesta orange-brown, not pruinose, 1.5-2.5 mm thick; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.