Swan Greenhood Orchid
Labellum
Ellura
Small White Sun-orchid
 
    
Swan Greenhood Orchid (Pterostylis ziegeleri)Class: Plant (Plantae) - Orchids
Order: Asparagales
Family: Orchid (Orchidaceae)
Species: Swan Greenhood Orchid (Pterostylis ziegeleri)
This Photo:     Comparison (Midget:Swan)
Synonyms: Hymenochilus cycnocephalus, Oligochaetochilus cycnocephalus or Pterostylis cycnocephala
Other name: Swan-headed green-hood

EXTRA - Photo Specific Information:
Here we have the Midget shown on the left, and the Swan on the right.
The point of the comparison is to show the difference in the labellum (tongue) of each species.
The rear of the labellum of the Swan (right) has a forward pointing growth; the Midget (left) is smooth.
The growth is right in the middle of the photo on the right.
While tiny, the difference is clear but difficult to detect as the labellum often closes when it is inspected.
General Species Information:
Found on Ellura (in the Murray Mallee)
Swan & Midget orchids look almost identical. The only differences are the rosettes in early life and the rear of the labellum when in flower. The rear of the labellum is not easy to see, so the flower head needs to be turned upside down to look inside, which then often triggers the tongue to close, hiding the rear of the labellum!
The rosette in early life is quite leafy. It shrivelled up when in flower.
The rear of the labellum has a forward pointing growth.
There was a question if this and P. mutica are synonyms. But they are listed as different species under the "Census of South Australian Plants", with no records of cross-breeding.
As we use Atlas (of Living Australia) as our name reference for ALL Australian species, as it's the only database we are able to download to check spelling; we will follow Atlas with this one.

Copyright © 2012- Brett & Marie Smith. All Rights Reserved. Photographed 12-Sep-2012
This species is classed as RA (Rare) in the Murray Mallee, by DENR (Regional Species Status Assessments, July 2010)