Gigantic evergreen trees with linear distichous or needle-shaped or scale-shaped and imbricated leaves and small solitary terminal cones. Flowers monoecious; males in globular stalked catkins. Scales of the cones woody and persistent. Seeds small winged, from 3 to 5 under each scale. There are but two species described, both of which are in cultivation. The derivation of the generic name is obscure, but it has been suggested that it is a modification of See-qua-yah, the name of a celebrated Cherokee chief.

1. S. gigantea, syn. Wellingtonia gigantea, Washingtonia gigantea, etc. Mammoth Tree. - A colossal tree with dense slender branches thickly clothed with small leaves at first needle-shaped and spreading, at length scale-like and closely imbricated and appressed, of a bright light green. Cone about 2 inches long, oblong; scales woody, persistent, wedge-shaped. This marvellous tree exceeds all others in its gigantic proportions, not excepting the enormous Gum-trees of Australia and Tasmania. One that was felled and stripped of its bark measured 327 feet in height, and 90 feet in circumference at the base; and another was discovered broken off at a height of 300 feet, where it was 18 feet in diameter, hence it is contended it must have been about 450 feet high altogether. It measured 112 feet in girth at the base. It is a native of .various parts of the Sierra Nevada in Upper California, where it was first discovered, it is reported, by an American hunting party in 1850. But the English collector, Lobb, appears to have been the first to introduce it into our gardens during the year 1853. It is also stated that Douglas saw it as early as 1831. However that may be, we may now count it by hundreds of thousands in this country, and some specimens have already attained a height of nearly 40 feet. Although this noble tree is generally known in this country by the name of Wellingtonia gigantea, we must remind our readers that from a scientific point of view this name is untenable, and must give way to that adopted by us, and now admitted by most botanical writers. Doubtless the tree will retain Wellingtonia as its popular name, in the same way as we call Pelargoniums Greraniums in common parlance.

2. S. sempervirens, syn. Taxodium sempervirens. Red-wood. - This also is a very lofty tree, towering to the amazing height of 200 to 300 feet. It was first discovered by Menzies in 1796, and until the species just described became known, it was justly considered as the ' (riant of the Forest.' Branches numerous, slender. Leaves distichous, linear, flat, acute, soft flexible, from 6 to 9 lines long, dark glossy green above, and silvery beneath. Cones about an inch long, nearly spherical, with thick woody scales terminating in a hard point. This species is scarcely so hardy as the Wellingtonia, but it will thrive well on well-drained soil, and grow at an extraordinarily rapid rate. A native of California.

Dammara is the last genus of this tribe, but all the species are tender. They are large dioecious trees with flat coriaceous leaves, and oblong or spherical densely imbricated cones with a solitary seed at the base of each scale. D. australis is the Kauri Pine of New Zealand.