196 Postetsia 
tains much volatile oil which gives it its charac- 
teristic odor. It is coarse-grained and _ splits 
readily, and is much used in the manufacture 
of shingles. The oil is antiseptic and preserves 
the wood from decay so that sound cedar logs 
of very great age are often found lying among 
and under the living trees of the forest. 
Thuja seedlings, as is common among the 
Cupressinee, have spreading, acicular leaves 
which are very unlike the adult foliage. These 
leaves are 3-10 millimeters long and are ar- 
ranged in decussate whorls of three or occasion- 
ally of four. Not infrequently one of the leaves 
of a whorl is displaced slightly above the others, 
and this seems to be uniformly true in the case 
of a leaf in the axil of which stands a lateral 
branch. Foliage of the mature form generally 
appears on some of the side shoots produced 
during the second year’s growth of the seedling, 
but the leading shoot maintains the juvenile 
form of foliage for several years. 
Cupressus. Linneus, Sp. Pl. ro0o2. 1753: 
Evergreen trees with small, scale-like, de- 
current leaves, and moneecious flowers. Stam- 
#3 J 
