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The Cycad Pages
Cycas schumanniana

Cycas schumanniana Lauterb., Fl. Schutzgeb. Sudsee: 154-155 (dated 1901) (1900).
"TYPE: New Guinea, 4 Sep 1896, Lauterbach 2745 (lecto (fide Hill 1994): WRSL (photo NSW))."


Etymology: Honouring German botanist Prof. Dr. Karl Moritz Schumann (1851-1904), curator of the Botanical Museum of Berlin from 1880-1994.

Illustration: Hill 1994a.

Historical notes: Described in 1900 by Karl Lauterbach, who directed the Neu-Guinea Compagnie, and built up a private herbarium and library. His main collections are held by the Wroclaw (formerly Breslau) Museum of Natural History (WRSL), now in Poland. Although dated 1901 on the title page, Lauterbach's publication was actually distributed in late 1900, and a copy was received at the British Museum of Natural History on 17 Nov 1900 (van Steenis-Kruseman and Stearn 1954).

This species was enumerated by Pilger (1926), and then placed in the synonymy of C. circinalis subsp. papuana by Schuster (1932). No further mention occurs in subsequent literature, and this taxon has been referred to either C. circinalis or C. media (eg. in herbarium sheet determinations from L, LAE and CANB). C. circinalis as now understood is an Indian endemic, and C. media is the Australian species that is most similar to the two New Guinea taxa in this group.

Distinguishing features: This species is nearest to C. campestris, differing in the larger leaves with longer and slightly broader leaflets that are distinctly angled forward on the rachis, the absence of adaxial mesophyll above the midrib, and the larger seeds. Male cones are larger and more elongate, and microsporophylls have a much less distinct apical spine. The megasporophyll is usually longer and more robust, and the lamina is somewhat narrower and has shorter lateral spines. C. circinalis is distinguished by a fibrous layer in the sarcotesta (which places it in a different subsection in the genus, Hill 1994a). C. media (sensu stricto, Hill 1992) may be distinguished by the laxer leaves and leaflets with thinner cuticle but more extensive hypodermis, the relatively narrower megasporophyll lamina with fewer, shorter, harder and more pungent lateral spines, and the longer sterile apex but shorter apical spine on the microsporophyll (C. media has a narrowly triangular megasporophyll lamina 35-90 mm long, 17-30 m wide, with 18-34 lateral spines 2-4 mm long and an apical spine 25-40 mm long. The male cone is ovoid, and microsporophylls have a sterile apex 8-11 mm long and an apical spine 6-10 mm long).

Distribution and habitat: Papua New Guinea, northern side of the island, predominantly in the Markham and Ramu River valleys, extending south along the Bulolo River valley as far as Wau.

C. schumanniana is the grassland species commonly occurring along the foothills of the Bismarck Range, in the Markham and Ramu valleys. It is locally abundant in savanna grasslands or less frequently in woodlands or forests with a dense grassy understorey. This species ranges from low to quite high altitudes, and has been recorded at 1600 m near Wau. All habitats are highly fire-prone, and regularly burnt, almost on an annual basis.

Conservation status: Apparently abundant over a wide range, and under no immediate threat of extinction.
Photo Ken Hill
Photo Ken Hill

Description:

Stems arborescent, to 2 m tall, 15-20 cm diam. at narrowest point.

Leaves bright green, highly glossy, 75-150 cm long, moderately keeled to flat (not keeled) in section (opposing leaflets inserted at 130-160(-180)° on rachis), with 80-210 leaflets, with orange tomentum shedding as leaf expands; rachis usually terminated by a spine 1-3 mm long. Petiole 15-30(-53) cm long (20-30(-50)% of total leaf), petiole glabrous, spinescent for 20-35% of length. Basal leaflets not gradually reducing to spines, 45-110 mm long.

Median leaflets simple, strongly discolorous, 120-230 mm long, 6-8.5 mm wide, inserted at 45-70° to rachis, decurrent for 3-5 mm, narrowed to 2.5-3.5 mm at base (to 25-45% of maximum width), 6.5-18 mm apart on rachis; median leaflets section slightly keeled; margins slightly recurved; apex aristate, spinescent; midrib flat above, raised below.

Cataphylls linear, soft, pilose, 80 mm long, persistent.

Pollen cones ovoid to narrowly ovoid, orange (pale), 12-30 cm long, 8-12 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 30-45 mm long, 15-20 mm wide, fertile zone 25-40 mm long, sterile apex 6-8 mm long, raised, apical spine prominent, sharply upturned, 4-11 mm long.

Megasporophylls 17-40 cm long, grey-tomentose and brown-tomentose; ovules 2-6, glabrous; lamina ovate to lanceolate, 35-100 mm long, 21-50 mm wide, regularly dentate, with 26-40 pungent lateral spines 3-6 mm long, 1 mm wide, apical spine distinct from lateral spines, 10-25 mm long.

Seeds flattened-ovoid, 32-39 mm long, 28-30 mm wide; sarcotesta orange-brown, not pruinose; fibrous layer absent; sclerotesta smooth. Spongy endocarp absent.


The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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