Tsuga occurs as genus of conifers in the family Pinaceae. A most common title hemlock is from either a perceived similarity in the smell of the crushed foliage thereto of the unrelated herb Poison hemlock; see hemlock for other senses of the word. Unlike a herb, a coinage of Tsuga are non poisonous. A title Tsuga is the Japanese name for Tsuga sieboldii.

A genus includes Niner coinage, tetrad inside North America and five within Asia. It is medium-size to big evergreen trees, 20-65 m tall, with conic to irregular crown shape & drooping branch tips. A leaves are needle-like, 8-40 millimeter hanker & One.Five-Three millimeter wide, intended spirally in a stem however twisted at the base to lie flat on either side of the shoot; it is green above & by having 2 white stomatal elastic beneath (however view T. mertensiana, following). A cones are pendulous, little (15-35 millimetre hanker; 35-70 millimetre around T. mertensiana), elliptical to cylindric, & matured within fall, 6-8 months fallowing pollenation. A seeds are very small, Two-Four millimetre hanker, by owning an 8-12 millimetre wing.

American Hemlock Tsuga heterophylla is the big mintage, reaching heights of Seventy m. These are the particularly most common timber tree in the Pacific Northwest of North America. These are besides deep-seated for timber around nor'-west Europe & other moderate areas by having high rain and cool summers.

Them mintage within eastern Northward America, Eastern Hemlock T. canadensis & Carolina Hemlock T. caroliniana, come threatened by the sap-sucking insect, the Hemlock Woolly Adelgid (Adelges tsugae). This aphid was introduced accidentally from either eastern Asia. Extensive mortality has occurred, particularly east of the Appalachian Mountains. A Asian coinage, & too them west U.s. hemlocks, come comparatively insubordinate to this pest.

Mountain Hemlock T. mertensiana is unusual within the genus in many respects. a leaves come less planate & ordered everthing spherical a shoot, & st& stomata above besides when following, generating a foliage a glaucous colour; & a cones come the longest in the genus, 35-70 millimetre yearn and cylindric like than prolate. the select few plant scientist deal with it around a distinct genus when Hesperopeuce mertensiana, though these are extra typically simply considered distinct at a rank of subgenus.

An additional coinage, Bristlecone Hemlock, 1st described when Tsuga longibracteata, is today treated within the distinct genus Nothotsuga; it differs from Tsuga around the vertical (non drooping) cones by owning exserted bracts, & male cones clustered inside umbels, in these features supplementary closely allied to the genus Keteleeria.