Which is why we were to be seen along the road verge at Linch Hill hunting for the tiny white flowers of the Cotswold pennycress Microthlaspi perfoliatum which is monitored by the Rare Plants Group in three locations in West Oxfordshire. Like many rare plants numbers fluctuate from year to year and it is hard to know exactly what conditions favour their survival. It seems that disturbance that creates bare soil or reduces the growth of more vigorous species helps to create an environment that favours the Cotswold pennycress. Rabbit grazing can also help as it keeps the sward short and there has previously been quite a lot of rabbit grazing at this site, but there was little sign of rabbit activity here this year.
A few drainage grips were created a few years ago and they seemed to provide a good environment for a while. But they are largely overgrown now and need to be cleared out and some new ones dug further along the road.
There are three plants that are very similar with tiny white flowers, Bittercress Cardomine spp and Whitlow grass Erophila verna, an identification of the Cotswold pennycress depends on the shape of the seed head. After a false start we were pleased to find 21 flowering plants so it is still hanging on in what might seem the most inhospitable of places. I am sure that anyone driving by would have wondered why we were staring so intently at a grass verge as the plant would not be visible to a passing motorist.