Close inspection of the seed heads of many species of rush (Juncus) at this time of year will almost certainly reveal the whitish cylinders made by rush case moths (Coleophora spp.) protruding like fat fairy cigarettes from the seeds of the plant like the one in the centre of the picture below.
Inside the case there is a larva or pupa which, next year, will turn into small, narrow-winged moth of similar colour to the larval case.
Distinguishing one species from another is only reliably done by breeding out the adults and then dissecting.
This photo was taken in the Wood Yard in Brede High Woods, but these Coleophora cases are common wherever rushes occur.