06 May 2014

Two locally scarce Pepperworts

100+ plants of Field Pepperwort at Sker Farm 30th April 2014
Last week I stumbled upon a good population of an unfamiliar Lepidium at Sker Farm, which I suspected was either Smith's Pepperwort Lepidium heterophyllum or Field Pepperwort Lepidium campestre. Both are scarce plants locally and their initial identification was not as simple as the key made it appear. A key character of Field Pepperwort are the vesicles on the seed capsules, these appearing as shiny bumps on the valves as shown below.
Ripening seed capsule of Field Pepperwort
showing  characteristic vesicles (shiny blobs)
As I coincidentally had plants of Smith's Pepperwort just coming into flower, grown from seed collected at Overton Mere last year from the last remaining two plants there, I was able to directly compare the flowers of the two species (too early for seed of Smith's Pepperwort). As can be seen in the image below, the most noticeable features of the inflorescence are the larger and more open petals of Smith's which also shows reddish undehisced anthers.
Smith's Pepperwort (left) and Field Pepperwort (right)
Thanks to Tim Rich & Arthur Chater for confirming the identification.


Charles Hipkin said...

Good to have the macro shot of the fruit for id purposes. I don't remember either species being anything other than scarce in Glamorgan in the past, so it's nice to see such a big population.

Barry Stewart said...

Glad to report that where the Gorse has been cleared at the Overton site, there is now not only an abundance of L. heterophyllum, but also a good number of plants of L. campestre. Well done WT site managers!