INTRODUCTION 3 



A. imhricata (the common monkey puzzle), but are enclosed within 

 the seed, the other in which the four seed-leaves are raised upon 

 a well-marked stalk. In the genera Torreya and Keteleeria the 

 cotyledons also remain enclosed within the seed. The number of 

 the cotyledons is very variable. In the Cwpressinece and Taxacece 

 they rarely exceed two ; when more than two, as in Pinus and 

 Abies, the number is often variable, ranging from 3 or 4, as 

 in Finns contorta, to 15 or 18, as in P. Sabiniana. 



The size of the cotyledons also varies greatly in different 

 species of the same genus. In Pinus Pinea, P. canariensis, and 

 P. Armandi they are ll- 2 in. long and proportionately stout, 

 while in P. contorta they rarely exceed ^ in. in length and are 

 very slender. The cotyledons are usually linear in form and in 

 some cases the midrib is prominent. In many species of Pinus 

 they are three-sided and in P. Strohus they are distinctly toothed 

 on the margins. The apex maybe pointed, as in Pinus, or blunt 

 and notched as in Abies. In some species of Abies, Pinus, and 

 Larix the cotyledons are longer than the primordial leaves 

 which follow. In certain species of Thuya and Cujiressus, 

 they are about the same length as the succeeding leaves. The 

 cotyledons usually fall away during the first year, but in Taxus 

 they persist until the third and in Abies until the fourth 

 year. 



Trunk and Branches. 



The relatively large development of the trunk as compared 

 with that of the branches is a characteristic of many conifers. 

 The verticillate arrangement of the branches, their spreading 

 direction and gradual diminution in size from below upward, give 

 rise to a tree of markedly pyramidal form, which depends mainly 

 on the alternate development and non-development of the buds. 

 In later life the tree generally loses its lower branches and the 

 branching at the apex becomes less regular. In cases where the 

 development of stem and branches is more equal, as in the yew, 

 a bushy habit is the result. This form becomes modified into a 

 fastigiate or columnar habit as the branches assume an upward 

 tendency, as in Libocedrus decurrens, while pendulous forms are 

 produced by the downward tendency of the branches. 



Buds. 



The buds of conifers are much like those of other plants in 

 their position and arrangement. A usual feature in the develop- 

 ment of the leading shoot is a terminal bud surrounded by smaller 

 buds, while in lateral shoots the terminal bud is often accompanied 

 by two smaller buds, which sometimes remain dormant. The 

 shape of the buds and budscales and their resinous or non-resinous 

 character often afford good specific characters. The young 



