The calciferous hills amongst which Jena nestles are protected nature reserves that are packed with the most beautiful wild-flowers. None struck me more than the throngs of purple and yellow wood cow-wheat (Melampyrum nemorosum) clustering in the hedgerows.
The purple 'petals' are actually new leaves, that turn green as they mature.
In German these flowers are called Hain-Wachtelweizen in German, which sort of means grove quail wheat. I didn't see any quails around here though.