Story: Orchids

Page 1 – Orchid habitat, features and conservation

New Zealand has over 120 native orchids, belonging to about 30 groups or genera. Some species are shared with Australia or have close relatives there, but over half are found nowhere else.

Perennials and epiphytes

Orchids are flowering perennial plants, belonging to the Orchidaceae family. Most New Zealand orchids grow as small ground herbs, dying back to an underground tuber after flowering and fruiting.

Eight species are epiphytes – they grow perched on trees or rocks. These ones don’t die back, and have thicker leaves.

Habitat

Orchids are found throughout the country, from coastal shores to alpine herb fields. Many species favour soils of low fertility, and poorly drained sites. Common habitats are mature forest, open scrublands and swamps.

Fungal partners

Orchids produce millions of dust-like seeds that can be blown long distances. The tiny seeds lack food reserves and cannot germinate until they have been infected by a soil fungus that supplies nutrients for the seed. This partnership persists throughout the life of the orchid, even when it develops green leaves and produces its own food through photosynthesis.

Some species are known as parasitic orchids. They depend wholly on their fungus partner because they lack chlorophyll and cannot photosynthesise food. New Zealand’s parasitic orchids are the potato orchids (Gastrodia species), a spider orchid (Molloybas cryptanthus) and Danhatchia australis.

Orchids in the oven

Traditionally, Māori people ate the tubers of orchids as snacks. Anthropologist Elsdon Best reported that the tubers of the potato orchid Gastrodia cunninghamii were dug in winter and dried by exposure. Known as perei, they were roasted over a fire, or cooked in a steam oven.

Flowers

Bizarre-shaped blooms are the most distinctive feature of orchids, and their common names – such as the spider orchid, flying duck orchid and helmet orchid – often reflect this. The showy part consists of an outer whorl of three sepals and an inner whorl of three petals. In most species the upper (dorsal) sepal forms a hood, which protects the interior reproductive parts of the flower from the weather. The middle petal (lip, or labellum) often forms an elaborately decorated landing platform to attract insects. The flowers of sun orchids (Thelymitra species) are unusual as their sepals and petals look the same.

The flowers of New Zealand orchids are small, ranging from tiny (3-millimetre diameter in Ichthyostomun pygmaeum) to the 5-centimetre-high hooded flower of tutukiwi, Pterostylis banksii.

Reproductive parts

Male and female reproductive parts in the middle of orchid flowers are fused into a structure called the column. Variations in the column and other flower parts promote insect pollination, or as is more common in New Zealand, self-pollination. The detailed structure of the column is important in identifying a species.

Smugglers

In 2004, two Czech orchid growers were prosecuted for trying to smuggle native orchids out of New Zealand. One was an inspector in the Czech Environmental Inspection Agency, the other the dean of medicine at Olomouc University. They were filmed taking orchids from a national park, and had over 100 plants when they were arrested. It is illegal to trade in orchids taken from the wild.

Conservation

A significant number of New Zealand orchids are rare, and some are endangered.

The rarest is the almost-black helmet orchid (Anzybas carsei), which holds onto a precarious existence in a single Waikato swamp.

Draining swamps and wetlands, and clearing forest for urban sprawl destroys the orchid habitat. The New Zealand Native Orchid Group was formed in 1982 to act as a forum for those interested in these unusual plants, and to promote their conservation.

How to cite this page:

Ian St George. 'Orchids - Orchid habitat, features and conservation', Te Ara - the Encyclopedia of New Zealand, updated 13-Jul-12
URL: http://www.TeAra.govt.nz/en/orchids/page-1