Systematics and Evolution of the Genus Cycas

A project undertaken at The Royal Botanic Gardens Sydney and supervised by K D Hill

The genus Cycas has a long history; fossil records extend over 250 million years. As a survivor from eras long past, the genus is of great intrinsic interest, and is also of cultural, religious and economic significance in many parts of the world. The evolutionary relationships between cycad species are poorly understood, although they are naturally distributed from China to Australia, and from Africa east to Tonga. Many are rare or threatened and a better understanding of the genus is essential if effective conservation strategies are to be developed.

The primary objective of this project is to study the systematics, evolution and conservation of cycads, particularly in the Asian region. In collaboration with several Asian botanists, a series of field study trips is being undertaken. The Asian material collected is also being examined in the herbaria at Kew, the British Museum of Natural History, the Linnean Society of London, Cambridge, Edinburgh, Dublin, Leiden, Bangkok, Hanoi, Saigon, Bogor, Kuala Lumpur and Paris. So far, seven field trips have been completed in China, Vietnam, Thailand, Malaysia and Indonesia.

As a result of these studies, one new species from Sulawesi has been recognised and named, fifteen undescribed species have been identified and several problems of typification, identification and nomenclature have been resolved. One taxonomic paper has been published, another accepted for publication, and a further five are at an advanced stage of preparation.

Discussions have been held with authorities in China and Vietnam aimed at developing cycad conservation strategies for these countries, and three papers based on the results of this project have been presented at international conferences in Malaysia and the USA.

The International Union for the Conservation of Nature is preparing a ‘cycad action plan’. The chapter for Asia has been written in collaboration with a number of botanists in the region.


Hill KD (1998). Identification and conservation of Asian cycads. Paper presented at the Flora Malesiana Symposium, Kuala Lumpur, July 1998, to be published in conference proceedings.

Hill KD (1999). A new species from Sulawesi. Kew Bulletin, 54, 209–213.

Hill KD (1999). Conservation status of the Asian cycads. Paper presented at the 5th International Conference on Cycad Biology, Miami, August 1999.

Hill KD, Hiep NT and Loc PK (1999) The cycad flora of Vietnam. Paper presented to the 5th International conference on cycad biology, Miami, August 1999.

Hill KD, Hiep, NT and Loc, PK (2001). A taxonomic revision of the cycads of Vietnam. Memoirs of the New York Botanical Garden (in press).

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Vietnamese botanists Prof. Ke Loc (L) and Nguyen Van Dzu (R) examine a new species of Cycas discovered in the Ha Long Bay World Heritage Area, Vietnam, during an expedition funded by the Hermon Slade Foundation, (photo: Ken Hill)

Vietnamese botanist Dr Nguyen Tien Hiep crosses a river near Khe San (known also for the American air base) in search of Cycas chevalieri, a species known only from the type specimen until rediscovered in a garden near Dalat, Vietnam, by an expedition funded by the Hermon Slade Foundation. (photo: Ken Hill)