Sun Spurge (Euphorbia helioscopia) behaves according to its name. Its green-yellow umbels always turn towards the sun and it flowers at the first sunny day at the end of winter.
Here are two tiny little specimens in a dry meadow.
The bracteoles make a kind of saucer on which sit flowers of the same pale green colour.
The plants here below are much bigger, they grow on richer soil in a rapeseed field. Each carries several umbels. Many leaves have already fallen off, and the long reddish stems are visible.
The flowers are visited by busy small insects.
The flowers are characteristic for spurges, they look a bit strange.
In this enlargement you can see cyathiums, structures with glands. In Sun Spurge a cyathium looks like a small basket with four eggs sitting on its rim. In the middle of the eggs you can see a bunch of stamens with pollen. From each cyathium emerges a short stem with a kind of slightly flattened ball. This is the female 'flower', and it carries three styles. The big darker green ball below is a female 'flower' that is growing out into a fruit that contains ripening seeds.
Here a seed got stuck between two bracteoles. The pale spot on top of the seed is an elaiosome, a tasty appendix especially designed to attract ants. They are wild about it and they carry them with the attached seeds to their nest to feed their larvae. The seed is not eaten and germinates next year.