THUJA. 321 



Gen. THUJA. Linnceus. Tlie American Arbor Vitse. 



Flowers, monoecious, or male and female on the same plant, 

 but separate ; the male catkins oval, the female ones solitary 

 and terminal. 



Cones, ovate-oblong, solitary, terminal, leathery, and smooth, 

 with a projecting tubercle below the apex of each scale. 



Scales, from four to six in number, in opposite pairs, and 

 mostly unequal in size. 



Seeds, in twos at the base of each scale, and furnished with a 

 transparent wing. 



Seed-leaves, in twos. 



Leaves, in opposite pairs, very small, scale-like, imbricated, 

 compressed, and in four rows. 



Name, derived from dvov, sacrifice, the wood when burnt 

 giving out an agreeable perfume like incense. 



All large evergreen trees or bushes, found in North America 

 and California. 



No. 1. Thuja gigantea, Nuttall, the Gigantic Arbor Vitse. 

 Syn. Thuja Craigiana, Jeffrey. 

 „ „ „ glauca, Lawson. 



„ Libocedrus decurrens, Torrey. 

 „ Abies microphylla, Rafinesque. 



Leaves, on the young plants awl shaped, somewhat lanceolate, 

 decurrent at the base, extended at the summit, and sharp- 

 pointed, loosely imbricated in four rows, thickly set on the 

 .branchlets in opposite pairs, the outer pair or marginal ones 

 being longest, and folded partially over the inner pair on both 

 sides, giving the young shoots a jointed, trident-like appearance. 



Leaves, on the adult plants, very small, scale-formed, one 

 twelfth of an inch long, and one twenty-fourth of an inch wide, 

 ovate, blunt-poiutcd, thick in texture, in close ojiposite pairs, 



Y 



