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Tuesday, 23 April 2013

The opening of a Hakea

There are two Hakea species in this 1917 line drawing. They are identified as Hakea acicularis (now Hakea sericea) and Hakea dactyloides.  The source is Florence Sulman's The Wildflowers of New South Wales, though the drawings are the work of "Miss D. Watkins". I have nothing on Miss Watkins yet, though a lady of that name taught at the Sydney Teachers' College when I did my teacher training.  I don't think there's a link, though.

Hakea sericea is known as needlebush, but a few of the species merit the name just as much, including H. teretifolia and H. gibbosa, which is the species I have used in the pictures below, because it came to hand on a bushwalk.

Hakea is a genus well-adapted to fire, with its woody fruits that open, right after a fire, or after a branch dies. To simulate this, I took two fruits from a tree in a dense patch and left them in an open Petri dish on my desk.

The time series speaks for itself:

Notice how the seeds have come loose, here. In the open air, they would probably blow away about now.

And finally, here are the loose seeds, and on the left, the empty fruit:

These seeds would lend themselves to all sorts of science projects: testing how far the winged seeds fall from a tree, whether they blow along the ground, how well the seeds germinate and more.

The unrelated she-oaks (Allocasuarina) also have woody fruits that protect the seeds from fire, and to do most kinds of Banksia, which are in the same family as the Hakea. The "gumnut" of the Eucalyptus is also woody and protects the seeds, buy I have never seen if they are winged or not.  That's fine as far as I am concerned: I always like to leave a few open ends.

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