S52 TREES 



All fir trees belong to the genus ahies, whose twenty-five 

 species are distributed from the Far North to the highlands 

 of tropical regions in both the Eastern and Western Hemis- 

 pheres. All are tall pyramidal trees, with wide-spreading 

 horizontal limbs bearing thick foliage masses, and 

 with bark that contains vesicles full of resinous balsam. 

 The branches grow in whorls and spread like fern fronds, 

 covered for eight or nine years with the persistent leaves* 

 Circular scars are left on the smooth branches when they 

 fall. 



The leaves are the distinguishing character of the genus 

 when cones are lacking. They are usually flat, two-ranked 

 on the twig, without stems, and blunt, or even notched at 

 the tip. For these typical leaves one must look on the 

 lower sterile branches of the tree, and back of the growing 

 shoots, where leaves are apt to be crowded and immature. 

 The cones are borne near the tops of the trees, and on these 

 branches the leaves are often crowded and not two- 

 ranked as they are below. The flowers of fir trees are 

 abundant and showy, the staminate clusters appearing on 

 the under sides of the platforms of foliage; the pistillate 

 held erect on platforms higher up on the tree's spire. Al- 

 ways the flowers are borne on the shoots of the previous 

 season. The cone fruits are cylindrical or ovoid, ripening 

 in a single season and discharging their seeds at maturity. 

 The stout tapering axis of the cone persists after seeds and 

 scales have fallen. 



The bark of fir trees is thin, smooth, and pale, with 

 abundant resin vesicles, until the trees are well grown. As 

 age advances the bark thickens and becomes deeply fur- 

 rowed. The wood is generally pale, coarse-grained, and 

 brittle. 



