CONIFERAE: THE SCOTS PINE 303 



and the Juniper (Juniperus communis) ; but many more are familiar 

 in cultivation in shrubberies and woods. Over the world at large 

 they include a number of other forms, somewhat loosely related, but 

 with common features that indicate their primitive character. Among 

 them are some of the largest and oldest of living organisms, such as 

 the Big Trees of California (Sequoia, see Frontispiece). Another well- 

 known and peculiar form is the Monkey Puzzle (Araucaria imbricata). 

 The seed of the Scots Pine, and other Conifers, produces on ger- 

 mination a seedling with a dominating main axis, which grows upright, 

 and keeps as a rule its radial construction. Radiating groups of 

 branches are borne at intervals upon it, which take a more or less 

 flattened form ; and as they do not grow so strongly as the main 

 stem the result is the pyramidial habit so well seen in the Christmas 

 Tree (Picea] and in the young Scots Pine. Sometimes this habit is 

 maintained throughout life ; but often, as in the Scots Pine, the form 

 becomes irregular as the tree grows older. The Coniferae are as a 

 rule closely gregarious, and they then form very exclusive forests. 

 The lower branches die off in the crowded woods, giving the clean 

 trunks without knots that are specially valued as timber. 

 . The Scots Pine, like most of the family, is characterised by leaves 

 of relatively small size, simple form and stiff texture. These are 

 xerophytic features, and are well illustrated by the " needles " of the 

 Pine. Their structure, with sunken stomata, a well-developed 

 cuticule, and a large proportion of bulk to surface bears this out. 

 Hairs are absent from their smooth surfaces. (Fig. 246.) 



In some of the Coniferae the vegetative leaves are all of essentially the same 

 type, as in the Juniper. But in the Scots Pine some of them are developed 

 as protective scales, others as green foliage leaves, and the mutual arrangement 

 of these two types is very characteristic. It is closely connected with the 

 fact that all the axillary buds do not develop alike. Those at the end of the 

 annual increment of growth are unlimited, and form the radiating group of 

 branches of each successive year already noted. Those lower down develop 

 only as limited foliage spurs, which remain short, bearing only a few mem- 

 branous scales, and distally two long green " needles " (Fig. 246). In the 

 seedling plant green foliage leaves may follow the cotyledons on the main 

 axis. But in the later stages the main axis and the woody branches bear only 

 scale-leaves, while the green needles are always borne on the foliage spurs. In 

 the different species of Pinus the number of needles on each spur varies : in 

 P. monophylle it may be only one. The Coniferae are mostly evergreens like 

 the Scots Pine. Yew, and Juniper. But some, like the Larch, shed their 

 leaves in autumn, or even their short leafy shoots, as in Taxodium. 



The root-system starts in all cases with a tap-root ; but it seldom 

 maintains its lead. Lateral roots arise from it, and they form the chief 



