This plant with scarlet flowers is currently (early summer) growing in
a Sydney park. The environment is regularly mown lawn.

The plant is growing among buffalo grass, and the leaves look for all
the world like that grass. The leaves have only ribs, so I guess it is
a monocot.

There is a hazel nut sized, but oval shaped, brown corm at the base of
the stem.

What is this plant?

http://www.box.net/shared/static/ipl86k6m2j.jpg