I'd actually gone to Eccleston Mere this morning to see how many species of grass I could find. In about a two hour period I was able to identify 20 species, as follows:
1. Soft brome - growing in the car park
Soft brome
2. Yorkshire-fog - abundant throughout
Yorkshire-fog
3. False oat grass - abundant throughout
4. Cock's foot - abundant throughout
5. Annual Meadow Grass - common, especially on footpaths and mown areas
6. Perennial rye grass - common throughout
7. Reed canary grass - common in SW corner and along ditches
8. Common bent grass - abundant throughout
9. Creeping soft grass - common, especially in SW corner
The hairy knees (nodes) of creeping soft grass are one of the best ways to tell it apart from the very similar Yorkshire fog.
10. Common couch - common in fields adjacent to the mere, dominant in places
11. Giant fescue - occasional along stream
Giant fescue
The overlapping auricles of giant fescue is a good way to recognise this grass.
12. Rough meadow grass - occasional especially along stream
13. Red fescue - common in fields, dominant in places
14. Crested dog's-tail - occasional in fields
15. Wavy hair grass - common on edge of woodland
16. Marsh foxtail - common on edge of arable field at end of stream
Marsh Foxtail
17. Timothy - common on edge of arable field at end of stream
Timothy.
18. Black bent grass - common on edge of arable field at end of stream
A field of black bent
19. Sweet vernal grass - occasional in fields
20. Tufted hair grass - locally common in fields
There will of course be other species, for example I'm amazed that I didn't find creeping bent which is one of the commonest grasses there is. It was almost certainly there, but I can't check every bent to see if it has stolens, and all of the bents I did check didn't have stolens.