Plant story

Paraisometrum mileense

A wild population of Paraisometrum mileense, thought to be extinct in the wild for 100 years, has been rediscovered in Yunnan, China.

Paraisometrum mileense, a species of the Gesneriaceae family, was described in 1998 by Prof. Wen-Tsai Wang, a Gesneriaceae expert from the Institute of Botany in Beijing (part of the Chinese Academy of Sciences (CAS)), during preparation of the Flora of China. Wang noticed that one Gesneriad specimen collected from southeast Yunnan was very distinctive from the others with regard to the corolla lobes and stamen arrangements. Together with his colleagues, he recognized and published this plant, in 1998, as the new genus Paraisometrum with a single species, Paraisometrum mileense, endemic to China and distributed only in southeast Yunnan. The specimen in the Muséum National d'Histoire Naturelle, Paris, collected 100 years ago by a French missionary, F. Ducloux, was the only evidence of P. mileense.

In the summer of 2006, Dr Shui Yuming and students from the Kunming Institute of Botany, CAS, found the wild P. mileense in Shilin County, in southeast Yunnan, during a seed collecting trip. According to a quick survey, ca. 320 individuals of P. mileense were found in this wild population, ca. 30% of them in flower. It was the first time since Ducloux's 1906 expedition that P. mileense had been seen in the wild.

Like most of the Gesneriads, P. mileense is a limestone-loving plant and only inhabits nutrition-poor and vulnerable limestone habitats in Yunnan. Due to the short distance from local settlements in the region and easy access, the habitat of P. mileense is greatly threatened by human activity.

It is greatly encouraging for botanists and conservationists to rediscover a species thought to be extinct in the wild and only to 'exist' in the herbarium. Dr Shui emphasises that the rediscovery of P. mileense provides people with an opportunity to understand its evolution, conservation, and potential utilization. Shui and his team are going back to the area to continue their unfinished work and will search extensively for other populations. Seeds will be collected and kept in the Germplasm Bank of Wild Species in Kunming for long-term conservation, seed biology study and other research purposes. Small living collections will also be introduced to the Kunming Botanic Garden in order to enhance public education and awareness.

Contact: Jie Cai