The rarest wild plant in Devon or is that Britain?

I went to Dawlish Warren yesterday to look for the Sand Crocus Romulea columnae. It only grows on the Warren and one other place  in the UK (Polruan in Cornwall). It was first discovered in 1834. Here is a little more information.

6 petals – stringy leaves

It is about 4mm across

It flowers from late March to April and the flowers only open in the sunshine