I've been searching online, over the past few days, in an attempt to identify the grasses within the metre and in particular those species responsible for the "fall out".
My knowledge is almost exclusively visually based, so I am not able to probe into the more detailed botanical sites at the moment. However, I now salivate at the prospect of the imminent arrival of Rodger Phillips' book, "Grasses, Ferns, Mosses and Lichens of Great Britain and Ireland".