[ Extracted from the Newsletter of the Friends of the Australian
National Botanic Gardens, May 1993. The
paper on this species is also available. ]
a New Species of Tea-tree from the Southern ACT
The genus Leptospermum is in the family Myrtaceae and comprises about 83
species. Commonly known as tea-tree or ti-tree, they are distributed in
Australia, South East Asia, New Guinea and New Zealand. Leptospermums occupy
a variety of habitats and are usually (but not always) found in wet or
periodically damp substrates.
During the course of applying a revision of the genus Leptospermum
to the ANBG Herbarium collection, two specimens collected by Phil Gilmour
(an ANBG associate collector) from the Scabby Range in the southern part of
the ACT during the summer of 1987-88 were obviously "a bit different".
After much checking of keys and descriptions, detailed comparisons against
available herbarium specimens of known species of Leptospermum and
discussions with colleagues, the possibility that the two collections
represented a new species became apparent.
To determine whether these collections really did represent a new species it
was necessary to undertake field work and make further collections of material
from all stages of development - buds, flowers, fruit and seed. Field work
allows botanists to see the plant in its living state, gain some understanding
of the species ecology and habitat preferences, delimit the distribution of
the species and sample variation in the population.
Between December 1991 and April 1992, four trips to the
Range in the
southern ACT were made by Herbarium and Gardens staff to collect material and
other information. As a more complete set of material became available, it
was obvious that the Leptospermum from the Scabby Range was indeed a
new species and one of
limited distribution and habitat preference,
essentially being restricted to a few exposed mountain summits - Mts. Scabby,
Kelly and Namadgi and Sentry Box Mtn. in Namadgi National Park and Scabby
Range Nature Reserve.
grows as a shrub, 20 - 50cm high in
exposed sites and to 1m in sheltered sites. It has small leaves that are
usually covered in white hairs that give the plant a silvery appearance. The
flowers are about 1cm in diameter with white or soft pink petals.
Having established that this Leptospermum was a new species, it had
to be given a name, described, illustrated and have its conservation status
assessed. All of these details and more are written up as a scientific paper
to be formally
in a botanical journal.
A name that referred to some aspect of the species geography was thought most
appropriate. Leptospermum scabbiensis - meaning literally the
Leptospermum from or of the Scabby area - was an obvious contender.
This was rather appropriate geographically speaking but did unfortunately
conjure up an unpleasant image of what the plant looked like and as such was
dismissed - it is after all a particularly beautiful plant! Thus,
Leptospermum namdgiensis - meaning the Leptospermum from or of the
Namadgi area - became the choice. Namadgi is the name given to the mountains
south-west of Canberra by the local Aborigines.
The description is an attempt to put into words all the important details -
such as leaf size, shape and pubescence, flower size and seed patterning for
example - that define the new species. This initially involves examining and
measuring many characters from all of the available collections - e.g., many
leaves were measured from all of the herbarium collections before stating that
Leptospermum namadgiensis has leaves from 3.5 to 9mm long and from
1.5 to 3.7mm wide.
Along with this written description is
showing details of the
species habit and anatomy. An illustration makes it a lot easier for readers
to visualise what the the written description is saying.
It is now accepted practice when naming a species that an assessment of its
conservation status be made. Many plants are under threat of extinction,
imminent or otherwise, and as such it is important that details of potential
threats, distribution and adequacy of reservation be published. This acts to
alert managers of conservation reserves and other authorities to the existence
of a rare or threatened species and prompts action to be taken to ensure its
continued survival. In this instance, Leptospermum namadgiensis was
coded as 2RCat. The "2" means that the species has a very restricted
distribution with a maximum distribution of less than 100km
(Leptospermum namadgiensis has a distribution of some 15km),
"R" refers to the species being rare but not currently considered
vulnerable or endangered, "C" denotes that the species is represented
within a National Park or other proclaimed Reserve (in this case
Namadgi National Park and Scabby Range Nature Reserve), "a" indicates the
presence of more than 1000 plants within the Park and Reserve and "t"
indicates that the entire known population of the species is within these
conservation Reserves. Even though Leptospermum namadgiensis has an
extremely limited distribution, the fact that all the individuals occur in
rugged, mountainous country within the boundaries of a National Park and
Nature Reserve mean that it is in no immediate threat of extinction.
was published in the March, 1993 edition of
Telopea, the National Herbarium of New South Wales (Sydney) journal
dealing with systematic botany.
Some work remains to be done with this Leptospermum. There are a
promising sites to be explored for the presence or absence of
Leptospermum namadgiensis - e.g. Mt. Morgan and Yaouk Bill Peak.
Also to be done is to examine the phylogenetic relationships between this
and other related species of Leptospermum - essentially how this
and other Leptospermum "fit in" with each other. In fact, another
new Leptospermum from Alpine National Park in Victoria has been
discovered. This one occupies a similar type of habitat and shares many
similar characters with Leptospermum namadgiensis - just how
similar these two are and their relationship with each other is still
unclear. This work is continuing.
Cuttings of Leptospermum namadgiensis were taken during the course
of the field work and brought back to the Nursery for propagation. Some
of these have been successfully struck and small plants are to be seen in
sections 2, 193, 194c and 195.
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