A tor is a hill in old English, the exact origins of the name escape me but it is certainly a hill. Tor-grass (Brachypodium rupestre), then, you expect to find on hills and to a degree it does although you can encounter it virtually anywhere the soil is chalky. Its other common name is the chalk false-brome which confirms its liking for chalk and confirms it is not a species of brome!
Tor-grass grows in dense clusters with lots of leaves emanating from a condensed area. The leaves are pale yellowish green and this makes it quite distinctive. It produces flowers in July which are upright with large seeds pods, similar to soft brome.
Tor-grass can be abundant on limestone cliffs near the sea in southern England and steps are being taken in places to try and reduce it through grazing to give other plants a chance. However, it is also the food plant of Lulworth skipper caterpillars and it could be that those measures are now having an adverse effect on Lulworth skipper population levels, the experts are still out on that one.