Cycas changjiangensis N.Liu is not an accepted species. It is a taxonomic synonym of Cycas taiwaniana Carruth., a tropical cycad of the genus Cycas endemic to Hainan Island and the far southern fringe of mainland China. The full species profile — taxonomy, ecology, morphology, conservation, and cultivation — is available on our Cycas taiwaniana page.
Why does this name exist?
Cycas changjiangensis was described by N. Liu in 1998 from material collected in Changjiang County (昌江县), on the western coast of Hainan Island. The name refers directly to this county. At the time of description, it was believed to be distinct from the other Hainan cycads — Cycas hainanensis (described 1975) and Cycas lingshuigensis (described 2004) — based on minor morphological differences in leaf and megasporophyll characters.
The molecular species delimitation study by Feng et al. (2021, Taxon) demonstrated that Cycas changjiangensis, along with Cycas hainanensis, Cycas lingshuigensis, and Cycas shanyaensis, is genetically indistinguishable from Cycas taiwaniana. All represent the same species — a single, variable, island-endemic cycad that had been described multiple times from different localities across Hainan. Under the principle of nomenclatural priority, Cycas taiwaniana Carruth. (1893) takes precedence over all later names.
This treatment is accepted by POWO (Plants of the World Online, Royal Botanic Gardens Kew), the nomenclatural authority followed by succulentes.net.
The broader pattern: one species, five names
The repeated description of Hainan cycads under different names reflects a common pattern in Chinese cycad taxonomy. Cycas species on Hainan are morphologically similar, vary subtly across their range (as most widespread species do), and were historically collected and described by different teams working independently in different counties. Without molecular data, each team concluded it had found a distinct species. Feng et al. (2021) revealed that this apparent diversity was an artifact of over-splitting — a frequent occurrence in groups with conservative morphology and wide intraspecific variation.
| Name | Author | Year | Type locality | Status |
|---|---|---|---|---|
| Cycas taiwaniana | Carruth. | 1893 | Cultivated (Kew), erroneously attributed to Taiwan | Accepted name |
| Cycas hainanensis | C.J.Chen | 1975 | Hainan | Synonym |
| Cycas changjiangensis | N.Liu | 1998 | Changjiang County, Hainan | Synonym |
| Cycas lingshuigensis | G.A.Fu | 2004 | Lingshui County, Hainan | Synonym |
| Cycas shanyaensis | G.A.Fu | 2006 | Sanya, Hainan | Synonym |
If you encounter a plant labeled Cycas changjiangensis in a nursery, a botanical garden, or a publication, it is the same species as Cycas taiwaniana. The cultivation requirements, conservation status, and biological characteristics are identical.
References
- Feng, X.Y. et al. (2021). Species delimitation with distinct methods based on molecular data to elucidate species boundaries in the Cycas taiwaniana complex (Cycadaceae). Taxon, 70(3), 477–491.
- Liu, N. (1998). Cycas changjiangensis, a new species. In: Proc. Sixth Int. Conf. Cycad Biol.