II. GYMNOSPERMS. 

 VEGETATIVE ORGANS. 



EXTERNAL CHARACTERS. 



A. Examine a plant of the common Norway Spruce 

 Fir (Abies excelsa), and observe that while the main 

 axis grows vertically upwards, and bears pseudo-whorls 

 of lateral branches, which radiate from it as a centre, 

 the branches themselves are ramified only in a hori- 

 zontal plane : the branches are thus dorsiventral, 

 having distinct upper and lower surfaces. 



The branches as well as the main axis bear numerous 

 simple, linear, four-angled foliage-leaves, which may 

 however have dropped otf from the older parts, leaving 

 clearly-marked scars. Note also at the bases of the 

 lateral branchlets, and at irregular distances along the 

 relative main branch or the main axis itself, that there 

 are zones where dry chaffy scale-leaves were inserted : 

 these protected the winter-buds when young, and their 

 bases remain persistent : the portions between successive 

 zones represent the annual increments of growth in 

 length, and, as the lateral branches are for the most 

 part inserted immediately below these zones of scales, 



