T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network


Pterostylis banksii

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Orchidoideae
Tribe: Diurideae
Subtribe: Pterostylidinae
Genus: Pterostylis
Species: Pterostylis banksii
Common name: Tutukiwi 

The New Zealand native genus Pterostylis is an interesting one in that it is distinctive by having flowers equipped with a mobile lip. This mobile lip is a pollination adaptation.  The pollinating insect lands on the flower, and alights on the lip.  Its weight causes the lip to tip, forcing the insect into a position where it pollinates the flower.

This greenhood orchid is a terrestrial tuberous herb and is one of New Zealand largest orchids which can grow up to 50cm tall. It has grassy often keeled leaves up to 25cm in length.  It has single 3 - 5cm high flower which is green with translucent white stripes. Tips of tepals range in colour from white to orange-red. Dorsal sepal very long, often slightly upturned at the tip. The petals are much shorter than the dorsal sepal. Lateral sepals diverge at a narrow angle, tips very long, erect or swept backward. Labellum tip is flat or arched with the top reddish. Stigma is long and narrow. The flower structure and colouring can be variable and they appear during October to December.