Two-bristle Greenhood Orchid
Flower - labellum closed
Murray Mallee Region
Two-bristle Greenhood Orchid
Flower - labellum, side
Two-bristle Greenhood Orchid (Pterostylis biseta)Class: Plants (Plantae) - Land Plants (Charophyta) - Land Plants (Equisetopsida) - Orchids
Order: Asparagus (Asparagales)
Family: Orchid (Orchidaceae)
Species: Two-bristle Greenhood Orchid (Pterostylis biseta)
This Photo:     Flower - labellum open
Other names: Rustyhood or Veined Greenhood

General Species Information:
Found in the Murray Mallee SA and possibly elsewhere
These are fascinating flowers. The two bristles are sensitive to motion. John Smyth tells us this is called an "irritable labellum". An insect will land on the labelum, attracted to the flower by scent. This will trigger the bristles to close the labellum, trapping the insect inside the flower tube. It's only way out is to follow the tube and escape. In the process is brushed against the pollen, thereby fertilising this flower, or taking it's pollen to another

Copyright © 2005-2023 Brett & Marie Smith. All Rights Reserved. Photographed 10-Oct-2005
This species is classed as RA (Rare) in the Murray Mallee, SA, by DENR (Regional Species Status Assessments, July 2010)