A tree usually 20 to 50, but up to 70 or 80 ft high in a wild state, with a reddish-brown trunk 2 ft or more in diameter; of slender columnar form in a young state, and shortly branched. The smaller ramifications are flat, two-ranked, and somewhat fan-shaped; the branching as a whole is bushy, spiral, and irregular. The trees shed their effete branchlets in fan-shaped pieces, 1 to 3 in. long. Leaves in four ranks, the lateral ones usually longer than those above and beneath, which are marked with a conspicuous raised gland; they are 1⁄16 to 1⁄12 in. long, pointed, the lateral ones spreading at the tips; dull grey-green. Cones 1⁄6 to 1⁄4 in. in diameter, globose, very glaucous; scales six, each with a triangular boss in the centre.
Native of eastern N. America, usually found in cold, swampy, often inundated ground; introduced in the eighteenth century. This tree was more frequently cultivated in earlier times, before the Californian and Japanese cypresses were introduced, than it is now. It is not so striking as they are, but is worth growing for its neat columnar habit. Although a swamp tree in its native country it will thrive better here in ordinary, deep, moist soil. In New Jersey immense quantities of trunks of this tree have been found immersed in swamps, many of them, although buried for hundreds of years, perfectly sound and not at all water-logged. It is very distinct in its branching from any other chamaecyparis. There are specimens of this conifer in the National Pinetum, Bedgebury, Kent, the best measuring 40 × 51⁄4 ft (1957) and 46 × 41⁄4 ft (1964). A few others have been recorded, but none larger than these.
cv. ‘Kewensis’. – Leaves glaucous; habit dense and broadly conical. Also known as ‘Glauca’.
cv. ‘Andelyensis’. – A very distinct form of dwarf, close, pyramidal habit; the main branches erect, the smaller ones very short. Besides the ordinary type of adult foliage it has branches with the juvenile type of leaf, longer and more awl-shaped. It appears to have been raised in a nursery at Andelys, in N.W. France, about 1850 (Retinispora leptoclada Gord.).
cv. ‘Ericoides’. – A dwarf, rather tender form with juvenile, needle-like leaves which originated in a French nursery in 1840 (Retinispora ericoides Gord.). But for the nurseryman’s statement that it was a seedling of C. thyoides it would be difficult to decide even to what genus it belongs (very similar forms have been produced by species of Thuja).
C. henryae Li – A tree to about 90 ft high, differing from C. thyoides in the following particulars: bark more shallowly fissured, with the ridges spirally twisted round the stem; branchlets less flattened; leaves lighter green, slightly longer and more appressed; juvenile leaves green beneath (not with two glaucous bands as in C. thyoides); cones larger, only slightly glaucous; seeds larger, with broader wings. A native of Florida and S. Alabama with its northern limit in Escambia county. It was described in 1962 (Journ. Morris Arb., Vol. 13, pp. 43-6) and named after the late Mrs Henry of Gladwyne, Penn., who had long studied these trees, previously considered to be C. thyoides, and brought them to the notice of botanists. It has proved hardy in the U.S.A. as far north as Philadelphia.