The name cedar is applied to a variety of trees, including species of several genera of Conifers, Juniperus, Thuja, Libocedrus and Cupressus.
The Virginian red cedar (Juniperus virginiana) grows in the United States, Canada and the West Indies.
The Bermuda cedar (Juniperus bermudiana) is used for internal joinery and is extremely durable.
The name Retinospora, therefore, does not stand for a true genus, but denotes persistent young forms of Juniperus, Thuja, Cupressus, &c., in which the small scaly leaves of ordinary species are replaced by the slender, needle-like leaves, which stand out more or less at right angles from the branches.
One of the best known examples is the Chinese juniper (Juniperus chinensis), in which branches with spinous leaves, longer and more spreading than the ordinary adult leaf, are often found associated with the normal type of branch.