The blue grass (Andropogon sericeus), is an annual of soft rapid growth, with a branching seed-stalk that breaks off and is blown by the wind in masses into waterholes; the blacks use the fine seeds of this grass for food. "Anthistiria membranacea," called the Flinders or Barcoo grass, is an annual of a reddish colour, found all over the western plains. It is soft and brittle, breaking easily off to fall on the ground, when stock will pick it up; it makes excellent hay, keeping sweet for years, and is one of the most fattening grasses. The varieties of the indigenous grasses that cover the great western plains are innumerable; all are more or less eaten by stock, even the triodia or spinifex that is looked on as a desert grass, and of a formidable and forbidding nature. Spinifex is a very drought-resisting plant, and in times of great scarcity and extreme drought, when all other grasses have dried out and been blown away, the spinifex is there with its erect spiney leaves, possibly bitter to the taste, but still life sustaining to stock, as has been proved in many a severe drought. It grows on sandy sterile ridges, and seems to adhere to the latest geological formation, the sandstone or cainozoic period; it is found on ridges adjacent to alluvial flats where the richest herbage and grasses are found in abundance. Kangaroo grass (Anthistiria ciliata), is found mostly in coastal districts, and although a good pasture grass when green, it soon dries and requires burning. There are two prominent varieties of spear grass in the north, the worst being the black spear grass (Andropogon contortus), which grows in sandy spots along the banks of creeks, or on sandy ridges; it is not of much use as a fodder grass, but becomes a terrible scourge to sheep when ripe and seeding. The seeds are barbed, and as sharp as needles, and having once entered the skin they work into the bone, causing intense annoyance and irritation, and ultimately death. The other spear grass (Andropogon Kennedeyii), not so dangerous, but of little use to stock, is a coarse-growing, strong grass, seven or eight feet high, with a reddish bloom, and strong seeds that penetrate saddlecloths and clothes in countless hundreds. Herbage fills the spaces between the tufts of grasses soon after the rains, and the plains develop a dense growth of pasturage; but after continued dry seasons, all herbage disappears, and the grasses follow in time, until very little is left except the roots, and a few of the more hardy salsolaceous plants. These form a striking feature in the economy of Nature in the plain country, the salt bushes are ever present in one variety or another, and help to keep stock in health and condition. The various species of "Atriplex" abound, and being very drought-resisting, they are reckoned amongst the most valuable fodder plants. Sir Thomas Mitchell was the first to make salt bush known after his first expedition over sixty years ago.