Thlaspi perfoliatum, Cotswold Penny-cress
What is it?
This species has declined dramatically with changes in modern farming. It is an autumn-germinating annual so autumn ploughing wipes out newly germinated plants and if that doesn’t then herbicides will. It now has Schedule 8 protection and is more commonly associated with quarries than arable sites. Of the four extant sites in Oxfordshire one is a quarry, and it is here that the plant is doing best, numbers being consistently high. The other sites include a road verge, an arable verge, and land at the top of a railway cutting. All the landowners are aware of the plant’s existence and are sympathetic to its needs.
Maintenance of a suitable habitat is necessary as bare ground is required for germination and the plant seems to be a poor competitor.
If you would like to help in this work, or take part in the monitoring of the species see the Oxfordshire Flora Group events programme.