PINACEAi; 35 



scale-like, small and usually glandular on the back ; those on the leading 

 shoot pointed and more or less spreading; on less vigorous shoots, rounded 

 and much compressed, the lateral pair nearly covering the dorsal and 

 ventral pair which are flattened. The leaves of juvenile plants and of some 

 species and forms are not scale-like but uniformly awl-shaped, pointed and 

 spreading. Flowers monoecious, solitary and terminal; the staminate 

 small, globose or cylindrical, composed of 3-6 stamens, each bearing 2-4 

 pollen cells on an orbicular connective. The pistillate flowers are minute 

 cones, composed of 4-6 pairs of scales, not all of which are fertile, the 

 fertile ones bearing 2-3 ovules each inside at the base. Fruit a small 

 ovate or oblong cone with leathery scales and usually 2 seeds to each scale. 

 Seeds small, usually winged. 



About 5 species in Central and Eastern Asia and North America. 

 Thujas may be distinguished from the flat-leaved cypresses by the cones, 

 which in the latter genus are usually globular in form and composed 

 of dilated or peltate scales, attached by the middle and in contact with 

 each other on the perimeter before the seeds are liberated. 



The Thujas are evergreen trees of generally pyramidal habit planted 

 mainly for their ornamental value. Numerous horticultural varieties have 

 been developed. Propagated by seeds; the varieties by cuttings. The 

 genus is divided into 2 sections, in China each section is represented 

 by 1 species. 



Thuja orientalis Linnasus.* 

 (Poh Shu.) 



A pyramidal tree 10 m. tall, or a dense, bushy shrub with thin, 

 reddish bark scaling off in thin, papery layers and upright or ascending 

 branches, bearing the much ramified sprays in a vertical plane. The 

 leaves are green on both sides, marked by a glandular depression on the 

 back; the leaves of the frond-like spray are closely appressed to the 

 slightly flattened axis; those of the more or less rounded lateral or main 

 axes are rhombic-ovate, with a free, acute and somewhat reflexed apex. 

 The cone is ovate-globose, erect, fleshy, bluish, later becoming hard and 

 woody, 12-25 mm. long; scales with a hooked spine on the outer surface 

 below the top, usually in 3 pairs, the upper pair sterile; the fertile scales 

 each bear 2 seeds. Seeds large, round and without wings. 



*See Frontispiece. 



