The statutory ages differ in the various states; in New South Wales and Western Australia it is from 6 to 13 years inclusive, in Victoria 6 to 12 years, in Queensland 6 to II years, and in South Australia 7 to 12 years inclusive.
Missouriensis (macrocarpa), 6 to 12 in., has stout trailing branches, lance-shaped leaves and large yellow blossoms; Oe.
P. dryopteris, generally known as oakfern, is a very graceful plant with delicate fronds, 6 to 12 in.
They germinate only in the second year after sowing; in the course of their first year the seedlings attain a height of 6 to 12 in.
It is a tall perennial grass-like plant, giving off numerous erect stems 6 to 12 ft.
It flourishes best in small tanks and ponds, in which the water is constantly changing and does not freeze; in such localities, and with a full supply of food, which consists of weeds, crumbs of bread, bran, worms, small crustaceans and insects, it attains to a length of from 6 to 12 in., breeding readily, sometimes at different times of the same year.
West Virginia, estimates that in fairly good producing sand a cubic foot of rock contains from 6 to 12 pints of oil.