Gastrodia longcolumn (Potato orchid)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
Order: Asparagales
Family: Orchidaceae
Subfamily: Epidendroideae
Tribe: Gastrodieae
Subtribe: Gastrodiinae
Genus: Gastrodia
Species: G. longcolumn
Binominal name: Gastrodia longcolumn
Common name: Potato orchid 

Gastrodia longcolumn is a leafless saprophytic orchid, one of New Zealand’s five native orchids in the genus: Gastrodia. They are commonly called Potato Orchids. The other New Zealand species are Gastrodia minor, Gastrodia cunninghamii, Gastrodia sesamoides, Gastrodia longcolumn "black" (a black form)

Gastrodia longcolumn has an erect, dark/light brown, leafless stem that grows up to 1 metre tall and can have a diameter up to 10 mm. The stem grows from a thick tuber.
The 60 odd 1.5cm olive green/dark brown flowers that appear during December and January are bell-shaped. The sepals and petals are joined together forming a tube (perianth). This is covered in small, light coloured, wart-like projections. The white 1cm long labellum has a yellow tip. The column is visible and is of a similar length to the labellum. The fruit is an oval-shaped capsule growing to about 15 mm long. Plants growing in dark shade often have darker flowers than those growing in well-lit locations.
Gastrodia longcolumn grows in the lowland to montane areas of New Zealand, from Lat 37S in the North Island south to Stewart Island.

1-Gastrodia longcolumn Potatoe orchid.jpg

Notice the labellum yellow tip
1-Gastrodia longcolumn Potatoe orchid-001.jpg

Thanks to Wikipedia for text and information: