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DENDROLOGY. 303 



its growth. It is never seen upon the uplands, among the beeches, 

 birches, etc., but is found on the rocky edges of the innumerable 

 rivulets and small lakes which are scattered over these countries, 

 and occupies in great part, or exclusively, swamps from 50 to 

 100 acres in extent, some of which are accessible only in the 

 winter when they are frozen and covered with several feet of 

 snow. It abounds exactly in proportion to the degrees of 

 humidity, and in the driest marshes it is mingled with the black 

 and hemlock spruces, the yellow birch, the black ash, and a few 

 stocks of white pine. In all of them the surface is covered with 

 a bed of sphagnum so thick and surcharged with moisture that 

 the foot sinks half-leg deep while the water rises under its 

 pressure. 



The arbor vitae is 45 or 50 feet in height and sometimes more 

 than 10 feet in circumference ; usually, however, it is not more 

 than 10 or 15 inches in diameter at five feet from the ground. 

 A full-grown tree is easily distinguished by its shape and foliage. 

 The trunk tapers rapidly from a very large base to a very slender 

 summit, and is laden with branches for four-fifths of its height. 

 The principal limbs, widely distant and placed at right angles 

 with the body, give birth to a great number of drooping, secondary 

 branches, whose foliage resembles that of the white cedar. On 

 the borders of the lakes, where it has room and enjoys the benefit 

 of the light and air, it rises perpendicularly, grows more rapidly 

 and attains a greater size than when crowded in the swamps, 

 where its thick foliage intercepts the light and impedes the 

 circulation of the air. In swamps its trunk is rarely straight, but 

 forms the arc of an ellipse or less inclined. Its sides swell into 

 two large ridges, which are a continuation of the principal roots. 

 The foliage is evergreen, numerously ramified, and flattened or 

 spread. The leaves are small, opposite, imbricated scales ; when 

 bruised they diffuse a strong, aromatic odor. The sexes are 

 separate upon the same tree. The male flowers, which appear 

 in the month of May, are in the form of small cones : to the 

 female blossoms succeeds a yellowish fruit about four lines in 

 length, composed of oblong scales, which open through their 



