Square-stalked St John's-wort, Hypericum tetrapterum

This hypericum reaches its best in mid-August and is a distinctive mixture of flower and fruit. The seeds pods turn boot-polish brown as they ripen which adds to the effect. The plants (which are said to prefer marshy places) have increased steadily in the past few years and it seems quite at home both in M3 and in The Waste.

Not many insects visit the flowers, but there are various things that feed on the leaves. One is the larvae of the tiny Johnswort pigmy moth, Fomoria septembrella, that make distinctive mines on some of the leaves. I have brought one leaf indoors to see if I can breed out an adult moth.