The Great Orchid Pretender

Actually there is more than one.

Frequently NOSSA receives a request to identify an orchid in someone’s garden.  Often, instead of an orchid (but occasionally there are orchids), it is the Ariasrum vulgare (common name Friar’s Cowl Lily or Cobra Lily).

Native to Asia and Europe, notably the Mediterranean and introduced to Australia, it is often mistaken for one of the flowers of the Pterostylis (Greenhood Orchids) or Diplodium (Shell Orchids).  Some have called it a Blackhood orchid others Snake Orchid.  It’s resemblance to the Greenhoods and Shell Orchids is superficial as they have none of the orchid features.  The dark purple hooded part is not the flower; it is a spathe (bract).  The flowers are minute hidden on deep down on the “tongue”.

The hood of the orchids is the combination of a deeply concave dorsal sepal interlocking with the lateral petals; and the fusing of the two lateral sepals.  Tucked away within the hood is the labellum (a modified petal) and the column (the reproductive organs of the flower).  The leaves of Ariasrum are quite large and distinctly different from any of the Greenhood orchids.

Friar's Cowl Lily 93RL

Arisarum vulgare amidst its large leaves

Pterostylis pedunculata 92RL

Pterostylis pedunculata (Maroonhood Orchid)

Diplodium robustum 92RL

Back view of a Diplodium robustum showing the dorsal sepal and two lateral petals that make up the hood of the flower

 

 

 

 

 

 

 

 

 

Diplodium robustum labellum and column 96HL

Looking into the Diplodium robustum – the labellum is the brown tip just visible at the front of the flower and the column is the brown white and yellow structure at the back

Pterostylis curta Labellum and column 92RL

Peering into the hood of a Pterostylis curta, the labellum is toward the front and the white and yellow structure to the back is the column

Friar's Cowl Lily open bract 93RL

The bract of the Arisarum vulgare has been split open to reveal the knobs which are the flowers. The flowers are so small a hand lens or microscope is needed to see them.

 

 

 

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