Thursday, December 1, 2011

Native Caper Tree

Capparis arborea

Franke Scrub at Highfields is a mass of butterflies at present, and this tree is one of the reasons. It’s a native caper, one of our five local Capparis species, and is host to at least four species of local butterfly.

This rather conspicuous plant is on the edge of the scrub. To find it, just drive around the edge and look for the butterfly-like white flowers and the butterflies that are hovering around it.

It’s worth looking for it in the morning, when the perfume of the fragile flowers is at its best. They only last a day, losing their petals by early afternoon.

This magnificent little tree may be several hundred years old, and is a good example of the naturally small dry rainforest trees which are so suitable for suburban gardens. Alas, they are sometimes undervalued - people who will see a large tree as old and therefore worth preserving may clear small ones because they don't appreciate that they, too are living relics of the pre-European era, so have heritage as well as environmental value.
This specimen's age is the reason that it is difficult to find the spines which are the most obvious identifying characteristic of caper species. They grow in pairs at the base of each new leaf, on all but the oldest trees. In seedlings, the spines are long and straight, but as the trees mature, they produce short, curved ones. Young trees might still have the remnant paired spines on their trunks, but older trees lose the prickly habit. Spines like this evolved as part of the "arms race" with herbivores. They protect the plants, which are otherwise very tasty, from being eaten, when it is young. Taller plants with sturdy trunks are not so vulnerable, so don't need the spines.
For more about this and other local Caper species, see articles posted November 2009, and December 2008.

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