Water Chickweed is a tall straggly plant growing in marshes and beside streams. Its flowers are up to 15mm across, with the 5 petals divided all the way down the their base. The leaves and stems are covered in sticky hairs.
This plant can be confused with Greater Chickweed, but is much hairier, and its petals are much longer than the sepals.

Hairy stem, leaves and calyx		Seed capsules