Members of the Tsuga genus of coniferous trees are popularly known as hemlocks, their common moniker stemming from the scent of their crushed leaves, which is said to resemble that of the unrelated herbaceous plant Conium maculatum, generally called poison hemlock. Despite their namesake, however, hemlock trees are not poisonous. The evergreens, which are native to North America and parts of Asia, are popular as ornamentals and grow best in locales that are humid and cool. Some species of hemlock have been cultivated as sources of tannin, a group of complex aromatic compounds primarily used for tanning and staining, and others are considered valuable for their wood, which is free from resin, nearly white, and moderate in weight and strength.