Early hair-grass

I have discovered a tiny grass, about 5cm high, growing and flowering in part of The Waste. It is early hair-grass, Aira praecox, and it must be one of the easiest plants in the world to overlook.

In addition to the one in flower there are two or three others in the same area not in flower. This is the bare patch I call 'Great Plantain Desert'. I have made this area of largely bare soil by simply weeding out most of the grass and other vegetation with my fingers. If a seedling appears, I leave it there until I have worked out what it is and I then decide whether to pull it up or not.

The mystery is how did the early hair-grass get there. I have not seen it eslewhere in the garden, though it is easily overlooked, and there are not many suitable habitats