Monday, 24 September 2012

Dune Gentians

Back at the beginning of the month I went out to measure the water tables at Braunton Burrows - something I usually do monthly to help maintain a long-running measure of the site's hydrological status. And out on one of the dune slacks, there was a plant in flower which I've been hoping to see there for quite some time: Dune Gentian - Gentianella uliginosa. OK, it's not exactly the most conspicuous of plants: these were only about 10cm tall at best, and it's not the most thrillingly obvious of plants: in fact it looks rather similar to its close cousin the Autumn Gentian (or Felwort) Gentinella amarella, but this is the only site in England where they grow. There are a couple of dune systems in Wales where the species is more abundant, and this may be the source of this population - much like the late lamented population of Fen Orchid Liparis loeselli - but there seems to be nowhere else in England (and perhaps the UK) where you can see this plant.
This is Autumn Gentian - a relatively large and robust species with numerous flowers and unmerous pairs of leaves above the basal rosette. The calyx is also clearly pressed tight up to the corolla, with just the tips of the teeth diverging.

This is the one. Smaller than amarella, with fewer flowers, fewer pairs of leaves and with calyx teeth unequal and coming away from the corolla.
Many grateful thanks to Dr Tim Rich at the Museum of Wales for confirming my identification too.