Saturday, July 6, 2013

Common Tussock Grass

Poa labillardierei 

Common Tussock Grass in summer, at the Bunya Mountains
“Poa” was the ancient Greek word for “fodder”. Nor surprisingly, most Poa species are important pasture grasses.
Poa is one of the oldest scientific plant names still in use, first given to a common European grass (Poa annua) in 1753 by Linnaeus, in his famous work “Species Plantarum” – the publication which began the modern system of plant names. There are now about 500 Poa species known, around the world They are so representative of “typical grass” that they have given the grass family,  Poaceae its name.

Our local species are attractive grasses which form dense, knee-high, weeping tussocks. Their graceful purplish flowerheads mature into conspicuous white seedheads, giving them the alternative common name “whitetop”.

This grass is seen to best advantage on the “balds” in the Bunya mountains, where it is the dominant grass.

The balds are appealing grassy patches sprinkled throughout the rainforest. They were originally maintained by aboriginal burning, to create “kangaroo grounds” for hunting. These remnants of Australia's cultural heritage are now slowly being invaded with weeds - although the National Park staff hope to reverse the process by learning and implementing a suitable fire regime.

This grass is probably the major host plant for the Banks’ brown butterfly (Heteronympha banksii mariposa), a beautifully patterned butterfly which spends most of its long adult life (it breeds only once a year) in the rainforest understorey.
Poa grasses were used by aborigines for making nets and string dilly bags.

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