Grass stem with ??

Grass stem with ??

Observation - Grass stem with ?? - UK and Ireland. Description: Several of these grass stems were visible on Selsley Common nr. Stroud Gloucestershire. this is old unimproved grassland, unsprayed and full of interesting wildlife. Not all stems of this grass had the swelling and some swellings didn't have the black fea

Several of these grass stems were visible on Selsley Common nr. Stroud Gloucestershire. this is old unimproved grassland, unsprayed and full of interesting wildlife. Not all stems of this grass had the swelling and some swellings didn't have the black feature at the upper end. On some there was a small hole into the swelling and inside it was empty.