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The Cycad Pages
Cycas zambalensis

Cycas zambalensis Madulid & Agoo, Blumea 50: 519-522. fig. 1. (2005). H—PNH


Etymology: The specific epithet refers to the name of the locality, Zambales, where this population is located.

Historical notes: This endemic species was discovered and described in 2005.

Distinguishing features: The species is easily distinguished from the other Philippine Cycas in having tomentose pinnae and rachis. The pinnae of C. zambalensis are also rigid and stiff, and the leaves are keeled. Based on these characteristics, the young individuals of C. zambalensis resemble C. revoluta, a common ornamental plant in the country. Cycas zambalensis is very similar to C. riuminiana (syn: C. chamberlainii), also found in the Philippines, in having long petioles (at least 25 cm) and very woolly megasporophylls. The species differs from C. riuminiana in having narrower pinnae, longer than wide sterile apex of the megasporophyll, larger apical spine on the megasporophyll,persistently lanate megasporophylls, and tomentose leaflets and rachis. The hairs persist even in dried specimens. The pinnae are short, rigid and stiff, and the leaves are keeled. The seeds are slightly flattened. A spongy endotesta was observed in one cultivated individual (Fernando 1605). This might represent present or past hybridization with subsection Rumphiae either in the ancestry of this group or this plant.

Distribution and habitat: San Antonio, Kawag, Bucao, Zambales, NW Luzon. Endemic. Cycas zambalensis is restricted to the ultrabasic grassy hills of Zambales, a distinct biogeographic region in the western part of Luzon Island. The plants are usually scattered wide apart on the hillsides and do not form distinct groups. Plants grow fully exposed to the sun and strong wind near the sea. The population dominates the seasonally dry, hilly grasslands of the Zambales Peninsula, which is distinct from the lowland evergreen rain forests of the Bataan-Zambales mountain range. The soils in the area are ultramafic and rich in chromite deposits. There are two pronounced seasons in the province: the dry season which is from November to April and the wet season for the rest of the year. Maximum rainfall occurs from June to September which coincides with the southwest monsoon.

Conservation status: the very limited distribution of C. zambalensis, changing land use of the habitat of the species, and increasing pressure from collection for the horticultural trade are serious threats to the species. It is considered a critically endangered species.The effect of occasional fire to the population has yet to be evaluated. IUCN (2001) Red List status DD/CR.

Description:

Stems arborescent to to 3m tall.

Leaves dark green, semiglossy, 110-190 cm long,keeled in section (opposing leaflets inserted at less than 180° on rachis), with 99–260 leaflets, with brownish tomentum not shedding as leaf expands; petiole 30–44 cm long ( 25–33% of total leaf), tomentose, spinescent for 60–80% of length; basal leaflets not gradually reducing to spines, 130 mm long.

Median leaflets simple,120–260 mm long, 5–8 mm wide, 5–10 mm apart on rachis; narrowed to 2.5 mm at base, margin straight; midrib flat above, raised below.

Cataphylls narrowly triangular, needle-like, 60–70 mm long, stiff, pilose.

Pollen cones brownish orange, ovoid to long ovoid, tapering, to 36 cm long, to 18 cm diam.; microsporophyll lamina firm, not dorsiventrally thickened, 30–50 mm long,10–30 mm wide; apical spine prominent, sharply upturned or gradually raised, 5–25 mm long.

Megasporophylls 22–35 cm long, densely brown-tomentose, tomentum persistent; ovules 4–6, glabrous; lamina ovate or lanceolate, 70–80 mm long, 40–50 mm wide,shallowly pectinate, with 20–34 pungent lateral spines 6–14 mm long, c. 1 mm wide;apical spine distinct from lateral spines, 30–35 mm long, 5–7 mm wide.

Seeds flattened ovoid, to 43 mm long, to 36 mm wide; sarcotesta yellow, not pruinose; fibrous layer absent; sclerotesta smooth; spongy endotesta present, thin.


The Cycad Pages

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Written and maintained by Ken Hill 1998-2010
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