Pollen of Tilia cordata (littleleaf linden or small-leaved linden)
A stamen of a littleleaf linden with pollen (yellow). A stamen typically consists of a stalk called the filament and an anther (green) which contains microsporangia. A pollen grain (here yellow) develops from a microspore in the microsporangium and contains the male gametophyte. The Tiliaceae family mainly includes tropical wood plants, only the linden occurs in Europe. It is a tree from the mixed deciduous forest on better soils, grows up to 25m high and the flowering period is June / July. The flowers have a leafy yellow-green subtending bract, that acts like a propeller and helps spread the seeds. Pollen can lead to allergic reactions in humans.
Scanning electron micrograph, magnification 70x (at 15cm image width).