IJ HABIT 7 



limits of perpetual snow in high latitudes or on lofty 

 Alpine ranges. 



With this introduction I pass to the subject of the 

 general habit of trees and shrubs. 



If we cast a glimpse at the various kinds of trees and 

 other woody plants growing in various parts of the world, 

 a task of no great difficulty in these days of photography, 

 it is obvious that a number of types may be easily selected 

 based on their sizes, shapes, and modes of branching and 

 of carrying their foliage. 



Conspicuous examples are at once furnished by the 

 Tree-ferns, Palms, Bamboos, and species of Pandanus, 

 Musa, Strelitzia, and Ravenala of the tropics ; the Papyrus 

 of the Nile ; the Yuccas, Aloes, and Agaves of Mexico 

 and S. Africa; the Draccena of Teneriffe and the curi- 

 ous Australian X author rhcea ; the CactaceaB of tropical 

 America, and the Stapelias and Euphorbias of S. Africa ; 

 the Casuarinas of Australasia, and the Ephedras of the 

 Orient and elsewhere ; the tropical 'Banyans and Man- 

 groves; the sub-arctic and alpine Heaths, and their 

 S. African and Australian representatives, to say nothing 

 of the curious Welwitschia of Damaraland, and numerous 

 lianas and stranglers and parasitic plants of various parts 

 of the globe. 



These are striking examples which have been noted 

 over and over again" by travellers, and many of them were 

 selected as types of vegetation by Humboldt and the 

 earlier pioneers of Geographical Distribution. 



But even our European trees and shrubs afford us 

 illustrations of the theme, as is evident if we compare and 

 contrast such plants as the creeping pine (Pinus Pumilio) 

 of the Caucasus and Pyrenees, with the erect pyramidal 

 Spruce (Picea excelsa) of Norway (Fig. 1), the spreading 

 and terraced Cedar of Lebanon (Fig. 6), or the umbrella- 



