The River Purwell is a chalk stream which rises near the area known as Purwell Ninesprings, a wetland habitat on the outskirts of Hitchin which is now managed as a nature reserve. When I was a child I was thrilled to discover what seemed to me to be like a swamp on the edge of my home town. I don't think there was public access then but I didn't let that deter my explorations.

 It's a haven for flora and fauna, comprising mixed deciduous woodland (including numerous Oaks) and a substantial section of reed beds.

 Purwell Ninesprings and the adjoining nature reserve Purwell Meadows form the floodplain of the river before it is channeled through residential neighbourhoods. 

 The course of the river emerges from Ninesprings and meanders through the meadows. I noticed these pretty blue flowers all along the shallow margins. At first glance I thought they were Water Forget-me-nots but looking more closely I think they are Blue Water Speedwells (Veronica anagallis-aquatica).

 Big clumps of Yellow Flag Iris (Iris pseudacorus) are dotted around the marshy parts of the open meadows. The long, pointed fronds are very noticeable among the grasses, sedges and rushes.

 The bright yellow flowers are just coming into bloom.

 Iris pseudacorus is an aristocrat of bogs and ditches.