Panicum capillare (Witchgrass)

Recently found to be widespread across the Rivernia district, It is unclear just how widespread this North American annual grass may be within the Canberra region.

Very similiar in appearence to the local hairy panic (P. effusum) which it seems to be replacing on the Riverina.  IIt is bigger than hairy panic, almost like it is on steroids. It's leaf blades are always wider than 5mm and frequently over 1cm while those of P. effusum are usually less than 5mm wide. The seed head is also more densely packed in comparison to the more open seed head of P. effusum.

Also very similar to another unwanted North Americam Panicum hillmanii, which is toxic to kangaoos and probably other native grazers.  The lemna, or outer bract surrounding the seed, in P. hillmanii has a dark moon crescent shaped scar at its base, while P. capillare doesn't. But report and pull out either of these grasse

Further reference: wikipedia