Richard Wright wrote in
:

I think the plant in question is a sedge (Cyperaceae).

It grows in a Sydney garden as a weed.

Does anybody know which species?

http://homepages.ihug.com.au/~richwrig/sedge1.jpg
http://homepages.ihug.com.au/~richwrig/sedge2.jpg



It is a flatsedge, or Cyperus. The species I don't know. Cyperus
includes ornamentals such as Papyrus, noxious weeds such as Nutsedge
(in addition to being a tasty snack, it is a horrid weed) and plants
of intemediate usefulness.

Sean