Journal Number 103
May 2007

VARIOUS CONTRIVANCES

Orthoceras novae-zeelandiae
The New Zealand terrestrial orchid flora is unique because most self pollinate:
the various contrivances by which the New Zealand orchids are fertilised by themselves are recounted here.

Bruce Irwin noticed that although the stigma faces directly away from the anther cap and pollinia,
and that the two are separated by a prominent rostellum, when he tried to pull the anther cap
backward, the pollinia remained stuck very firmly to the back of the stigma. In fact they were stuck
by penetrating pollen tubes, indicating that Orthoceras novae-zeelandiae can be self pollinated
from behind the stigma.

Actually, it would be very hard for an insect entering the flower to come into contact with the
pollinia through that small triangular opening framed by the prominently jutting two sides of
the anther cap and the rostellum.

O. novae-zeelandiae may be an obligate selfer.