Annual meadow-grass (Poa annua) has to be the most common grass species of ground that is frequently disturbed and can be found almost anywhere! It is one of those 'conflict' species that people plant where they want it (lawns, putting greens, football pitches, fodder crop) and try to get rid of where they do not want it. You can buy annual meadow-grass seed and, almost along side it in the garden centre, a herbicide that seeks to control it and then, a bit further on, a fertiliser to make it grow thick and green ... are we not a funny creature?
Annual-meadow grass is a low growing, creeping grass that, if left uncut, produces a flower spikelet with branches that produce white florescence that in turn make hundreds of seeds. It is fast growing which is why it is popular but I should say it is not the generally preferred choice for lawns. The leaves are pale green and this gives it its common name in the USA, blue-grass.