Kew's Millennium Seed Bank - Extinct Plants Project

The Extinct Plants Project team have extracted seeds from specimens of extinct plants held in Kew’s Herbarium.

Interior of the Herbarium at Kew where over seven million plant and fungi specimens are housed

Extinct Plants Project

The Herbarium of the Royal Botanic Gardens, Kew is at the forefront of the science of plant classification. Its ever-growing collection, started in 1853, currently holds over seven million plant and fungi specimens. This is the world’s largest collection of historical plant specimens, representing nearly 98% of known plant genera.

Kew staff have recently documented the extinct plant species in this enormous collection to create the Extinct Plant Database. This information will provide an important source of information for research that aims to understand more about plant evolution and even possible causes of extinction.

About the project

When specimens of plants and fungi are stored in a Herbarium they are documented, identified, and placed within their correct family group. They are usually dried, pressed and glued on a sheet of paper with the relevant labelling. Kew’s Herbarium includes approximately 1,000 specimens that are known to have become extinct. Until the Extinct Plant Database was created, information about them was not easily available to botanists.

The majority of the world's seed-bearing species produce what is known as ‘orthodox’ seed which can withstand drying. Once dried, aging is slowed for these seeds which in some cases can be viable (able to germinate) for many years. Researchers have previously reported cases of seeds from herbarium specimens successfully germinating hundreds of years after they were collected. In many cases the specimen sheets for extinct species in Kew’s Herbarium may have viable seeds attached which may be the only remaining ’living’ tissue of the species. ‘Resurrecting’ such species could lead to opportunities for propagation and ex situ conservation or even repatriation of living plants.

The Extinct Plants project team have extracted seeds from specimens of extinct plants held in Kew’s Herbarium. Finding seeds that can be germinated is no easy task: herbarium samples are usually collected from plants in flower since that is when they display the features generally used for identification. As a result, specimens are less likely to be collected from plants that are ready to shed their seed. If a specimen does have seeds, in many cases they are severely damaged or the seed embryos are not fully mature. Despite these difficulties, the team has so far found nine species with seed suitable for germination trials.