CHAPTER IX. 



SYNOPSIS OF THE GENERA OF CONIFERS. 



In order to present the genera described in this work 

 arranged in their proper sub-orders, the following synopsis 

 has been prepared. It is intended as an artificial key to 

 aid in determining the genus to which a plant belongs, 

 rather than as a scientific grouping of the genera. The 

 number placed after the name of the genus refers to its 

 position in the work. The characters of the Family are 

 described at length on page 12, and we here give only a 

 brief recapitulation of them: 



NATURAL ORDER CONIFERS, THE PINE FAMILY. 



Trees or shrubs with a resinous juice, and mostly linear, 

 scale-formed or awl-shaped, and entire leaves. Flowers, 

 monoecious or dioecious, without calyx or corolla, usually 

 crowded into short, scaly aments. Ovules and seeds, nak- 

 ed. Embryo in the axis of the albumen. Cotyledons, 

 two to many, in a whorl. The wood destitute of ducts, but 

 the fibre marked with numerous circular disks. 



SUB-ORDER I. THE PINE SUB-FAMILY ABIETINE J3. 



Fertile flowers in aments, consisting of scales each 

 from the axil of a bract, and bearing at its base two in- 

 verted ovules ; fruit a cone. Buds, scaly. 



A Flowers monoecious ; leaves persistent. 



* Seeds 2 to each scale of the cone and adherent to it. 



Pinus (PINE.) 1. Leaves needle-shaped ; 2, 3, or 5 

 in a cluster, with a scaly sheath at base. 



Abies (SPRUCE. FIR.) 2. Leaves short, needle- 

 shaped, 4-sided or flat, scattered on the branches or some- 

 what 2-rowed, not clustered ; cones with thin scales. 

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