''Pterostylis agathicola'', commonly known as the kauri greenhood, is a species of
orchid endemic to the
North Island
The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New Zealand, separated from the larger but much less populous South Island by the Cook Strait. The island's area is , making it the world's 14th-largest ...
of
New Zealand. As with similar greenhoods, the flowering plants differ from those which are not flowering. The non-flowering plants have a rosette of leaves flat on the ground but the flowering plants have a single flower with leaves on the flowering spike. It grows almost exclusively in kauri (''
Agathis australis'') forest and has a relatively large green and transparent white flower.
Description
''Pterostylis agathicola'' is a terrestrial,
perennial,
deciduous,
herb
In general use, herbs are a widely distributed and widespread group of plants, excluding vegetables and other plants consumed for macronutrients, with savory or aromatic properties that are used for flavoring and garnishing food, for medicinal ...
with an underground
tuber and when not flowering, a
rosette of two or three dark green, linear to lance-shaped leaves. Each leaf is long and wide. Flowering plants have a single flower long borne on a spike high with three or four spreading stem leaves. The flowers are translucent white with green stripes and brownish tips. The
dorsal sepal and
petal
Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...
s are fused, forming a hood or "galea" over the
column
A column or pillar in architecture and structural engineering is a structural element that transmits, through compression, the weight of the structure above to other structural elements below. In other words, a column is a compression member. ...
. The dorsal sepal is much longer than the petals and curves forward with a long, tapering tip. The
lateral sepals are erect leaving a wide gap between them and the galea, and there is a deep narrow notch in the centre of the
sinus between their bases. The
labellum is long, about wide, curved, dark green to brownish, twist prominently to the right and protrudes above the sinus. Flowering occurs between July and October.
Taxonomy and naming
''Pterostylis agathicola'' was first formally described in 1997 by
David Jones,
Brian Molloy and
Mark Clements from a specimen collected in the
Waitākere Ranges. The description was published in ''The Orchadian''.
Distribution and habitat
The kauri greenhood only grows in kauri forest, often in leaf litter close to large trees. It is found on the North Island between Te Paki Recreation Reserve, the Te Kauri Scenic Reserve and the
Kaimai Range.
References
{{Taxonbar, from=Q15491889
agathicola
Endemic orchids of New Zealand
Plants described in 1997