Bitter Vetchling is really a pea rather than a vetch.. This is why its scientific name is Lathyrus and not Viccia. Its is also sometimes referred to as a Heath Pea and it actually looks more like a pea in that the flower is more rounded and not as elongated as the vetches. Also the flower head only has a small number of individual flowers (four or five is usual) where as some of the vetches often have quite a lot more. Another more pea like characteristic is that the leaf has a wing like margin along the petiole.
The flower starts of as a Deep Purple colour, it fades with time and becomes more of a blue colour. The photographs here were taken at Symonds Yatt Rock. This made me think of ‘Deep Purple in Rock’ I was never that much into Deep Purple, seemed a bit pretentious to me. In the heavy rock genre I preferred early Lead Zeppelin ( early because they became quite pretentious by their 4th album) I also quite like Black Sabbath. but this does not have so much to do with Bitter Vetchling.
The five sepals are fused together into a little tube and resemble a night cap, they are a very dark purple/blue colour. The typical pea flower has the upright petal know as the banner is slightly lighter in colour and if you look carefully you can see slightly darker purple veins. Visible in the close up below.
This photo of the leaf shows the winged edge, the stems are angular and also edged with a narrow wing. The leaf does not have a tendril. This species just produces a rudimentary spine at the end of its compound leaf.
It is quite common occurring in heathy meadows, lightly grazed pastures, grassy banks and open woodlands; also on stream banks and rock ledges in the uplands. However according to the BSBI it is not found that much in East Anglia and the East to central Midlands.
Germaine Greer has written an article in the daily Telegraph about this species under the heading of Heath Pea. Along with Deep Purple, I am also not a great fan of Germaine Greer or the Daily Telegraph but to be fair the article is worth a look.