How are the plants collected?

Carefully pressing a specimen Carefully pressing a specimen to ensure that all plant parts are visible

Collecting large palm fronds Collecting large palm fronds can pose a challenge. Palm expert John Dransfield collects another specimen

Drying specimens A stove being used to dry specimens in the plant press

loading specimens on a donkey Transporting the presses back to base

laying specimens in a folder Sorting material for distribution to herbaria

Traditionally plants have been pressed between sheets of newspaper (to absorb the moisture). A special plant press, designed for the purpose, is used and the plants dried, under a low heat, using purpose-built stoves or by leaving the press in the sun (possible in hot, dry climates). These techniques are still used today and Kew botanists have developed presses and stoves that both allow the plants to dry as quickly as possible (conserving as much of their original colour and features as possible) and are highly portable (since they need to be used in remote places). Pressing and drying the plants as soon after collection as possible also helps to preserve their original colour and shape. Historically, a regular chore during expeditions was to change the newspaper in the presses to dry the specimens more quickly. Today, many botanists will use large sheets of blotting paper, cardboard and corrugated sheets of aluminium in between the specimens to ensure they dry quickly.

How are plants included in the collection?

Material usually comes either from expeditions undertaken by Kew staff in collaboration with partners from the host country or as an exchange with another Herbarium from among our international network of collaborating institutions.

When the dried plant material arrives it is submitted to two procedures:

  • a series of checks is carried out to ensure that the relevant documentation and collecting permits are in order
  • the plants are placed in quarantine in freezers (at -35°C) for three days in order to kill insects that may still be on the plant and that would put the rest of the collection at risk.

Herbarium Catalogue