The writing diary of a well-mellowed science writer who cares about the public understanding of science and knows the ropes. This blog bounces between my curiosity, the daily realities of professional writing, the joy of pursuing nature, and my recycling of ideas that won't be in some book or other as far as I can see, but still needed sharing. I welcome comments and suggestions! Spam will be blocked and reported. For my books, see http://members.ozemail.com.au/~macinnis/writing/index.htm
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Thursday, 22 September 2016
Johann Wolfgang von
Goethe had a bit of a thing about leaves. He was z poet, so he wrote a poem about the leaf of the
Ginkgo, probably because he saw the leaf as
a symbol of love. Goethe was many things, and also a curious botanist—some
might even say a peculiar botanist. He thought the leaf was the basic unit of the
plant: "from top to bottom a plant is all leaf…".
I thought of this when I
sighted a Lomatia (right) along one of the North Head tracks a few weeks back. At least, I think it was a Lomatia, but now I have my doubts, because of where it was growing.
I'll need to visit it later in the year to check the flower, but Lomatia is one of those
That started me thinking about distinctive leaves, like
Canada's maple leaf, the serrated leaves of the Banksia (left) and the gracefully curved leaves of some gums.
seen, never forgotten, though I'll bet that somewhere out there, some other
plant has taken on a similar design. That's why botanists, both before and after Goethe, used flower parts for identification, despite Goethe's ideas. Still, leaves help in identification, and they are certainly worth attention.
A leaf is just a plant's
way of catching sunlight, while hopefully not losing too much water. Most
Australian plants have tricks to hang onto their water.
She-oak needles (right) are
really branches with the leaves tightly attached, all except for little scales
Every walk brings me "leaves" to admire, but
some are fake leaves like those on Bossiaea (left) which are really cladodes, that being a fancy name for flattened stems.
Then again, the leaves of wattles are often
phyllodes, flattened petioles or leaf stalks, and in each case, the change is
designed to save the plant from losing water.
Another way to avoid losing water is to discourage
animals from eating the leaves. Biting a leaf opens wounds that the plant
"bleeds" from, and what is eaten represents a loss as well.
Rainforest leaf, unidentified.
That explains this
rainforest leaf, which I saw on the Dorrigo Plateau, has such nasty spines,
though as you can see, small animals just dodge around the spines.
Listen, young Goethe, forget about plants as symbols of
love—even the leaves remind us there's a war on out there. Some leaves are even