Many grasses flower in May. Also this Fern-grass (Catapodium rigida) that shows off the little whitish stamens that cover its spikelets, as if somebody sprinkled them with sugar.
Grasses (Poaceae) are anemochores, they need the wind to disperse their pollen. Not that easy to take advantage of the wind if you are small and low on the ground.
Apparently, Fern-grass manages well, it flourishes notwithstanding its small size. It grows everywhere in arid spots where there is not much other vegetation. Like a limestone meadow on dry soil, between the gravel on a path, or, as here above, on a stone wall.
It does not really look like a fern.
More like a toothbrush. Its spikelets are in two rows both turned towards one side.
For a plant so tiny it is rather conspicuous, even between more colourful Trefoils you cannot not see it.