Confidence: I'm as sure as I can be.
Notes: Just adding the Latin, which I regret is likely to cause much confusion. It's this sort of thing which gives taxonomists such a bad name. The common deergrass used to be T. cespitosum subsp. germanicum. There was rather rare subspecies, subsp. cespitosum. Then someone decided to upgrade them to full species. OK, no problem. Except the rules of taxonomy. T.cespitosum subsp. germanicum became T.germanicum, and T. cespitosum subp. cespitosum became T. cespitosum. This means of course that all those records simply recorded as T. cespitosum without subsp. separation now have to change their name, and the general name given to a common plant has now been swopped to a rare species. Very helpful.