Emma Cooper

As it’s the last day of herbarium week (and I hope you’ve enjoyed your tour as much as I did!) I could be cruel and leave you guessing as to what these wonderous final specimens might be. But I won’t :)

This is the fruit of the raffia tree – the same one that produces the papery string kids use for art projects and gardeners use for tying back plants. The shiny surface is entirely natural; it hasn’t been laquered or polished.

And this is gum arabic, the hardened sap of one of two Acacia species. Gum arabic is a food additive, E414, used as a stabiliser. It’s also used in paints and pigments.

These ‘antlers’ are in fact pneumatophores, the breathing roots of mangroves. They stick up out of the surface of the waterlogged soil, allowing the plant to survive in low-oxygen conditions.

A seed pod from Afzelia africana, an African legume. When the pods are ripe they split open, leaving the seeds dangling from threads. They hang out to attract birds, who will eat them and disperse them far from the parent tree.

An impressively long seed pod, from Cassia grandis, a tree from Honduras. Small flowers are followed by these pods, which can take up to two years to mature.

And the biggest seed of them all, Coco de mer, endemic to the Seychelles. Although this plant is protected by CITES, Will and Kate were given a seed as a wedding present; due to its suggestive shape it is considered to be an aphrodisiac.

Dr Harris could not show us the specimen sheet for Coco de mer, or any of the other species that are endangered and protected. In the past, nefarious individuals have used the location information held on the sheets to find and exploit remaining populations.

The herbarium also has to have a license for all of the controlled narcotic plants in the collection. They have managed to avoid having to apply for an anti-terrorism license to hold their specimen of ricin – the highly toxic plant that is commonly grown in gardens, is not controlled and for which I was handed seeds in a seed swap last year.

In a tour lasting a couple of hours it is impossible to get a handle on the sheer volume of botanical wealth held in the Oxford University herbaria – a collection which is quite modest on the world scale. Digitization is a slow process, but is bringing herbaria into the 21st century. Hopefully those who believe the physical specimens can then be destroyed will be out-voted, as the historical value and sheer beauty of these collections is as irreplaceable as their contribution to science has been.