The Cycad Pages
Cycas bifida

Cycas bifida (Dyer) K.D. Hill, Bot. Rev. 70(2): 161-163 (2004). H—K

Etymology: From the Latin bi- two and -fidus divided, referring to the dichotomously divided leaflets.

Literature: Cheng, Fu & Cheng 1975 (as C. micholitzii).

Illustrations: Wang 1996 (as C. multifrondis,)

Historical notes: This remarkable species was first recognized as a distinct taxon in western literature by English botanist Sir William Thiselton-Dyer in 1902, who described it as C. rumphii var. bifida, on the basis of a leaf fragment collected by H- B- Morse in the Longzhou district of southern Guangxi in 1896. Thiselton-Dyer later received material apparently collected by W Micholitz in Annam (northern Vietnam) from Sander & Sons in 1905, and from Henry Ridley of the Singapore Botanic Gardens at about the same time. He described this as a new species C. micholitzii in 1905, noting the similarities with the specimen he had earlier described as C. rumphii var. bifida but not combining the two. Subsequent authors have regarded them as the same species until recent studies have shown them to be distinct.

Distinguishing features: The most immediately striking feature of this species is the dichotomously divided leaflets. However, this also occurs in several related taxa, and in a horticultural form of C. revoluta that is popular in Japan. The subterranean habit, the small, soft microsporangiate cones, the loose, freely peeling sarcotesta lacking a fibrous layer and the verrucose sclerotesta are also all features shared by a wider group of related species (Section Stangerioides). Within this group of related species, C. bifida is distinguished by the long leaves with glossy, thin-textured, comparatively long and broad leaflets that are dichotomously divided very near to the base. It is most similar to C. micholitzii from central Vietnam, and can be distinguished by the larger stature, the longer, broader and glossier leaflets and the larger male cones with microsporophylls lacking an apiculus.

Distribution and habitat: Southern Guangxi and eastern Yunnan provinces in China and Cao Bang, Lang Son and Tuyen Quang provinces in north Vietnam. Locally abundant but many populations are now seriously depleted. This species occurs in low, scrubby but fairly dense mixed evergreen and deciduous or bamboo woodland, often on red terra rosa soils on and around steep karst limestone outcrops, but also on sandy or loamy soils over shales, granites metasandstones.

This species is apparently sympatric with C. multipinnata in several populations in China, and a range of morphologically intermediate forms that can be interpreted as a hybrid swarm has been observed (see C. longipetiolula, excluded names, below). Hybrids are also recorded with C. dolichophylla and C. diannanensis.

Conservation status: This species has been severely reduced in numbers both by collecting and by unrestrained agricultural and forestry development. The rarity combined with the unusual habit make it a very highly sought plant by collectors. It is still, however, frequent in many places, especially in Vietnam, and not considered to be immediately at risk. IUCN (1994) Red List status VU A2c.

Vernacular: chaye sutie (China).

The Cycad Pages

© 1998-2012 Royal Botanic Gardens Sy dney
Written and maintained by Ken Hill 1998-2010
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