Blue fleabane

Today we made our last survey visit to Houghton Regis Chalk Pit, accompanied by Chris, Alex and our friend John, who came for some work experience to support his university application. While we were on site we met up with another of the ex-students from Alex's course, who's doing a six month internship with the Wildlife Trust. They were both very surprised to see each other!

I'd asked them to map and estimate the population size of the Chiltern gentians - but this proved to be an almost impossible task, as this species occurred over a much wider area than I'd realised. The methodology had to be revised at lunchtime otherwise they would have still been counting next week! I've still got to do the calculations, but there must have been many tens of thousands of this beautiful species, making it one of the largest populations in the UK.

While they were working on that, I made sure I'd visited all parts of the site, and knew exactly what vegetation was present. The quarry is huge - and with some very steep slopes! I discovered quite a few corners that I hadn't had a chance to visit on my earlier trips, though I didn't add too many more species.

The blue fleabane Erigeron acris was in full flower. This annual species is quite a frequent coloniser of chalk and sand pits. It's normally rather understated and easily overlooked, but this specimen was particularly fine and shows how the flowers gradually change colour from a somewhat washed out mauve to a more intense purple.

Needless to say the work took quite a bit longer than I'd hoped, so we ended up travelling back home during the rush hour. By the time we arrived home, I wasn't in a fit state to go shopping, so we had an impromptu Chinese meal, which pleased everyone.