Insight into Slender Bird’s-foot-trefoil (Lotus angustissimus): native and described as ‘very local’ in south and south west England, it is very similar to Hairy Bird’s-foot-trefoil (Lotus subbiflorus) but it flowers in heads of only 1-2 flowers (rather than 3-4) and the keel, the lower edge of the lower petal, has a right-angled bend (rather than an obtuse angled bend).
It flowers in July and August.
UPDATE: after a helpful comment from Doctor French and Ian Bennallick (see below) it seems likely that this specimen is actually not Slender Bird’s-foor-trefoil but a variety of Common Bird’s-foot-trefoil (Lotus corniculatus), possibly var. carnosus or var. crassifolius. A site visit next summer for confirmation is called for!
Related pages: Wild flower posts | British wild flowers gallery
Doctor French and Ian Bennallick
Many thanks for your comment and I apologise for the slow response as we greatly appreciate the contribution of experts in any field.
Our references don’t list all the varieties of Common Bird’s-foot-trefoil (Lotus corniculatus) and made no mention of the narrow leaves and longer calyx so I’m sure you’re right. I will re-visit the site next summer, hopefully with a more detailed key.
I have added an update to the post and thank you again for your helpful guidance.
Dr Colin French
Ian Bennallick and I have both looked at your photo (we are the Botanical Society of the British Isles Recorders for Cornwall and we agree the plant is not Lotus angustissimus. We think the plant is Lotus corniculatus, as the leaves are not narrow enough for L. angustissimus, and the calyx lobes are too short. It’s difficult to see if the plant is a perennial or not. In Sell and Murrell Vol 3 2009, there are 8 varities of Lotus corniculatus. Looking at the photo and reading the descriptions, and assuming it is a perennial, it is closest to L. corniculatus var. carnosus, though var. crassifolius has been recorded for Kynance in Davey and Lizard in Thurston and Vigurs. Could this be var. crassifolius?