Kerria
Credits
Roderick Cameron (2025)
Recommended citation
Cameron R. (2025), 'Kerria' from the website Trees and Shrubs Online (treesandshrubsonline.
Family
- Rosaceae
A genus of a single species (Kerria japonica), akin to Rhodotypos, but differing in its yellow, five-petalled flowers and one-seeded fruit (achenes), versus white, four-petalled flowers and 1–4 clustered drupelets in Rhodotypos. Together with Neviusia and Coleogyne, it forms the tribe Kerrieae, sister to Exochordeae (Exochorda, Oemleria and Prinsepia) in the subfamily Amygdaloideae of the Rosaceae.
The genus came into being when De Candolle rescued what is now K. japonica from taxonomic uncertainty, which saw it pass through Rubus and then Corchorus (Malvaceae). De Candolle was able to determine its status as a distinct genus by examining plants of a double-flowered form that were in cultivation thanks to an introduction in 1805 by William Kerr, in whose honour he named the genus (De Candolle 1818).
Kerr was a Scottish gardener employed at Kew. Sent to China in 1803 by Sir Joseph Banks to collect plants for Kew, Kerr was the first botanical collector to reside in China for more than a few weeks. His collecting was limited to acquiring plants in nurseries, which he sent back to Britain. He stayed in Guangdong, with excursions to Java and the Philippines, until 1812, when he was appointed Superintendent of the Ceylon Botanic Garden. He died two years later, apparently from illness related to opium addiction, presumably picked up while in Guangdong: a contemporary press notice mentioned that he was unable ‘to prosecute his work in consequence of some evil habits he had contracted, as unfortunate as they were new to him’ (Cox 1945, Wikipedia 2025). He sent back to Britain examples of 238 plants new to European gardeners, including what would be named Rosa banksiae, in honour of his benefactor’s wife, Lady Banks (Aiton 1811).