20 BULLETIN 680, U. S. DEPARTMENT OF AGRICULTURE. 



Obviously, however, use of the name pine for these trees is a per- 

 version, for in all respects the pines are totally different trees. 

 Properly, moreover, they should not be called firs, from which they 

 differ greatly in the character of their wood, foliage, and cones. 



False hemlocks are evergreen trees with dense, soft, foliage- 

 Their branches, which grow from the trunks in irregular circles, form, 

 with their many side branches, wide fanlike sprays. The rough, 

 thick-barked gradually tapered trunks are tall, straight, and, in the 

 case of one species, very massive. They have broadly pyramidal 

 crowns, which in the case of young trees extend down to the ground. 



The flat, bluntish leaves, with contracted bases, are single and 

 spirally arranged on the twigs and branches. They appear often to 

 grow mainly from two opposite sides and from the top of the branches, 

 but by a twist in their stems the lower leaves are bent upward 

 toward each side of the branch. Leaves of a season's growth remain 

 on the tree from about five to eight years. In cross section the leaves 

 show two resin ducts situated near the edge on the underside. 



The male and female flowers are each borne singly on different 

 parts of the same tree, the twigs on which flowers are borne being 

 formed the previous year. The female flowers, bristly, scaly bodies 

 which develop into cones with seed, are borne nearly or quite at the 

 ends of twigs, while the male flowers, scaly bodies bearing pollen only, 

 grow from the bases of leaves farther back from the ends of the twigs. 

 Most characteristic of the false hemlocks are their pendulous cones 

 with conspicuous 3-pointed, scalelike bracts, which protrude from 

 among the cone scales (PI. VI). None of our other native evergreen- 

 leafed conifers that bear cones with persistent cone scales produce 

 exserted bracts. The thin-scaled cones mature in one season, soon 

 afterwards falling from the trees. Two-winged seeds (PL VI, a) are 

 borne under each cone scale. Their large, light wings permit the 

 wind to distribute them easily. The seed-leaves of Pseudotsuga are 

 flat and vary in number from 6 to 12, being commonly 6. 



The trees of this group are of the greatest commercial importance 

 (mainly one species), supplying great quantities of the finest and 

 largest saw timber of any of our native trees, if not of any trees in the 

 world. The slightly resinous, pinelike wood is suitable for all sorts 

 of construction purposes. 



Two species of this group are natives of North America. One is 

 distributed more or less from the Rocky Mountain States to the 

 Pacific coast, extending also into adjacent Canadian and Mexican 

 territory, while the other species inhabits the mountains of southern 

 California. 



Species of this genus are of ancient origin, the wood of some of them 

 having been found in the Middle Tertiary period of western Canada, 

 while remains of Pseudotsuga taxifolia occur in the Pleistocene of 



