Pterostylis - Greenhood, probably P. vittata or Banded Greenhood. Pterostylis have 300 species divided into greenhood, snail & shell orchids. About 82 species are endimic to Western Australia. The Hood is formed by the combined dorsal sepal and petal. The lower two sepals form a "door" that is sensitive and snaps upward when a small insect like a gnat or mosquito lands on it. The insect is trapped until the door opens again in about a half hour. I unsuccessfully tried to trip the door with a grass leaf, but while I was there one of the doors opened and a gnat flew out. The lowest flower in this pic shows the door clearly open. Others are also seen in following pics.
Close-up of the hood.
Probably Pterostylis sanguinea or Dark Banded Greenhood. Common in Kings Park (Perth.) Both this and the P. vittatta seem to prefer to live beneath Sheoaks (Casuarinaceae)
Close up of hood with door shut. There may be a pollinator trapped inside.
