Volume 44A of the Flora of Australia documents four subfamilies of the grass family Poaceae, describing 80 genera and 405 species. The largest subfamily is the Pooideae, a predominantly temperate group with many annual species. It includes the large endemic genus Austrostipa, an important component of native pastures, but one which also contaminates wool and injures stock with its penetrating 'seeds'. Poa, also largely endemic, grows mainly in southern areas of Australia, and is characteristic of higher altitudes. The subfamily also includes our most important grain crops, wheat, barley, rye and oats, and introduced temperate pasture grasses. There are also many weedy genera such as Briza and the economically significant Nassella. The largely tropical Bambusoideae are poorly represented in Australia, with only three native species and another three naturalised. Many ornamental species of 'bamboo' are grown in Australia, but few have become naturalised. Also tropical is the subfamily Pharoideae. It includes Leptaspis, with its strange inflated florets,the subject of the cover painting.
The final subfamily, the Ehrhartoideae, contains another important grain crop, rice, as well as the widespread weedy genus Ehrharta.