Close-up View of the "Geraldton Waxflower"
by Brian Johnston (Canada)
Geraldton Waxflower is often used by florists in cut-flower
arrangements. Although it is widely available, the plant is
native to western Australia where it grows as an evergreen shrub in
gardens, and along roadsides. It is considered to be one of
Australia’s most famous wildflowers, and this popularity has spurred
the development of plants with many different colourations (white,
yellow, pink, purple, lilac, and bicolours). Surprisingly, it is
in Israel that much of the physiological and horticultural research on
this species has been done. Most Waxflower plant material in
Europe originates from that country. In North America, plant
material usually originates in California or Mexico, although Peru is
also a producer. Australia itself sells to most of the world.
The genus name Chamelaucium is
probably from the Greek - chamia meaning
“dwarf” and leucos
meaning “white”. Uncinatum means
“hooked”, and refers to the tips of the needle-like leaves. The
Waxflower is a member of the Myrtle (Myrtaceae)
The first image in the article, and
the one below, show the main characteristics of the plant. The 10
to 15 millimetre diameter flowers in my sample were pale yellow, tinged
with pink. Many bright green needle-like leaves about 25
millimetres long contrast with the woody brown stems.
A close-up of a portion of the main
stem reveals this rather strange looking branching point, with two
larger diameter green flower stems, and two narrower diameter
yellow-green leaf stems.
Each of the tiny flowers contains
five waxy petals, and has a dark pinkish-purple centre.
The following images show the
before and after appearance of a bud about to bloom. Notice that
the sepals (modified leaves)
are fused in this species to form a scalloped, cone-shaped base (or calyx) for the flower. Notice
the interesting depressions and colouration of the calyx in the second
The mature flower contains one
central pistil, composed of
the stigma and supporting style, (the female, pollen accepting
organ), and a variable number of stamens,
(about 15), composed of anthers
and their supporting filaments,
(the male, pollen producing organs).
Three of a flower’s petals have
been removed to show the distinctive narrowing of the style from bottom
Notice the ring of reddish anthers
in the following image. Also notice the circular shape of each
petal, and the narrow connection of the petal to the circular “floor”.
An interesting variation in
structure makes the stigma of a Waxflower a real “pollen magnet”.
Tiny sticky hair-like filaments extend out into space from the central
A side view of a stigma under the
microscope can be seen below. Most of the sticky hairs shown in
the previous two images have been removed by the manipulation necessary
to get the specimen into position on the slide, but several are still
visible. The yellow material seems to be a semi-solid, sticky
glue-like substance quite different from that of the stigma itself,
(the red elliptical structure).
Higher magnification of one of the
hairs reveals that it is not of constant diameter.
The cellular structure of the style
is shown below.
A photomicrograph of an anther and
filament follows. Note the tiny rice-shaped pollen grains
sticking to the anther’s surface in the right hand image.
I placed a small quantity of the
sticky material coating the surface of the stigma onto a slide, and
used phase-contrast illumination to study the sample.
Unfortunately, I have been unable to find out what the unusual
flat-tipped triangles are.
The transportation of Waxflower
cut-flowers to distant locations around the world is difficult.
One problem is that the buds and flowers tend to fall from the main
stem, (a process called abscission),
during the process. Two solutions to the problem have been
found. One is to hydrate the plants in refrigerated water.
The other involves dipping the cut flowering shoots in a chemical
called auxin, a plant hormone. The chemical name for this
substance is indole-3-acetic acid
(IAA). Auxin’s structural formula and molecular shape are
shown below. (Forgive me, but my chemistry teaching background
just asserts itself every once in awhile!) Both images were
produced by HyperChem Pro.
Although most of my wildflower
articles concern native Ontario plants, I find it rewarding during the
winter to visit a florist or horticultural centre to obtain specimens
from other parts of the world. The botanical diversity of our
planet is truly amazing!
The photographs in the article were
taken with an eight megapixel Sony CyberShot DSC-F 828 equipped with
achromatic close-up lenses (Nikon 5T, 6T, Sony VCL-M3358, and shorter
focal length achromat) used singly or in combination. The lenses screw
into the 58 mm filter threads of the camera lens. (These produce
a magnification of from 0.5X to 10X for a 4x6 inch image.) Still
higher magnifications were obtained by using a macro coupler (which has
two male threads) to attach a reversed 50 mm focal length f 1.4 Olympus
SLR lens to the F 828. (The magnification here is about 14X for a
4x6 inch image.) The photomicrographs were taken with a Leitz SM-Pol
microscope (using a dark ground condenser), and the Coolpix
More information concerning the
Geraldton Waxflower can be obtained from the following sites:
wax and relatives :
use of native (Australian) plants :
Microscopy UK or their contributors.
Published in the June
2006 edition of Micscape.
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