the Tallong Midge Orchid of course!
One of the
rarest plants in Australia and listed as an endangered species,
Genoplesium plumosum, more commonly known as the Tallong Midge
Orchid, only occurs in a few small pockets in and around Tallong, and
no where else on the planet.
at right, is displayed with the kind permission of Paul Holmes of
locations of the species are characterised by having very shallow soils
overlying flat to gently sloping sheets of sandstone. The surrounding
vegetation is low scrub/heath dominated by Violet kunzea (Kunzea
parvifolia), Common Fringe-myrtle (Calytrix tetragona) and Eggs
and Bacon (Dillwynia sp.) to name a few, and native grasses such as
kangaroo and wallaby grass. Five other autumn flowering Midge Orchids,
with which the Tallong Midge Orchid could be confused, also grow at the same
sites, along with several other orchid species. At all sites the habitat is
surrounded by Brittle Gum (Eucalyptus mannifera) and Scribbly Gum
(E. rossii) low woodland.
is almost impossible to detect except when flowering. The
flowers occur on a single stem up to 20cm tall with 1-8 smalll
flowers, about 5cm across, clustered at the top of the stem. The flowers are
green with purple stripes and a reddish purple tongue. The
almost leafless stem is very thin and about 10-15 cm long, superficially like
a blade of grass.
Very little is known about the biology of Tallong Midge Orchid. Midge
orchids in general die back after flowering and fruiting and exist only as a
dormant tuber for much of the year. During either spring or
autumn (depending on the species), they will produce a single erect stem. The
flower spike emerges through the leaf near the apex of the stem. Midge
orchids don't necessarily flower every year, often skipping years when
rainfall hasn't occured prior to the flowering period.
As far as
the Tallong Midge goes, initial observations suggested the species flowers
4-6 weeks following good autumn rains. However, this flowering behaviour
appears to vary. In autumn 2000, even after plentiful autumn rains, no
flowering specimens appeared, despite several searches at sites where the
species was observed flowering the previous year.
contrast, despite average rainfall in late summer/ early autumn 2001,
numerous plants flowered at most previously known sites. Although successful
flowering and reproduction is likely to be dependent on favourable weather
conditions, the specific factors that influence flowering behaviour is poorly
Pollination biology of the Tallong Midge Orchid isn't known, but most
Midge orchids are said to be pollinated by vinegar flies, although some are
self-pollinating (Jones 1988).
As far as
damage by fires goes, it's thought that little impact on the species would
result, unless they were extremely hot. The only exception might be if fires
occured whilst the plant was flowering or fruiting.
Ability of Species to Survive
no immediate threats to most of the populations, and providing
other potential threats can be controlled with the cooperation of landowners
and Mulwaree Shire Council, there appears to be no reason why the Tallong
Midge Orchid can't be maintained in the wild in the long term.
had good rains in early February, and autumn is now upon us, it's nearing the
time when our Tallong Midge Orchid should make its annual appearance ...if
all is well. So find the magnifying glass and some kids (they're closer to
the ground) and start combing the landscape ...see if you can discover some
new colonies. Good luck!
further information, or if you *think* you've discovered a new colony,
contact the National Parks and Wildlife Service in Queanbeyan on 02