Tsuga, a genus of conifers in the family Pinaceae. There are eight, nine, or ten species (depending on the authority), with four species occurring in North America and four to six in eastern Asia. Unlike poisonhemlock (Conium), the various species of Tsuga are not poisonous.
The Irish strata yield two ferns; 7 Gymnosperms, Cupressus, Cryptomeria, Taxus, Podocarpus, Pinus (2 species), Tsuga; and leaves of about 25 Dicotyledons.
Abies, Tsuga, Larix, &c., the mesophyll is heterogeneous, consisting of palisade and spongy parenchyma.
Nageia) a canal occurs below each vein; in Tsuga, Torreya, Cephalotaxus, Sequoia, &c., a single canal occurs below the midrib; in Larix, Abies, &c., two canals run through the leaf parallel to the margins.
The hemlock spruce (Tsuga canadensis) is a large tree, abounding in most of the north-eastern parts of America up to Labrador; in lower Canada, New Brunswick and Nova Scotia it is often the prevailing tree.
The Douglas spruce (Pseudo-tsuga Douglasii), one of the finest conifers, often rises to a height of 200 ft.