PHYSIOGNOMY OP PLANTS. 25 



winged insects, and sometimes that of the birds which are 

 attracted by the perfume of the honey vessels. Such is 

 their number and variety that, to mention only a limited 

 district, the entire life of a painter would be too short for 

 the delineation of all the magnificent Orchidese which adorn 

 the recesses of the deep valleys of the Andes of Peru. 



The Casuarina form ( 22 ), leafless, like almost all species 

 of Cactus, consists of trees with branches resembling the 

 stalks of our Equisetums. It is found only in the islands of 

 the Pacific and in India, but traces of the same singular 

 rather than beautiful type are seen in other parts of the 

 world. Plunder's Equisetum altissimum, EorskaFs Ephedra 

 aphylla from the north of Africa, the Peruvian Colletias, 

 and the Siberian Calligonum pallasia, are nearly allied to the 

 Casuarina form. 



As the Banana form shews the greatest expansion, so 

 the greatest contraction of the leaf-vessels is shewn in 

 Casuarinas, and in the form of Needle trees ( 23 ) (Coniferae). 

 Pines, Thuias, and Cypresses, belong to this form, which 

 prevails in northern regions, and is comparatively rare within 

 the tropics : in Dammara and Salisburia the leaves, though 

 they may still be termed needle-shaped, are broader. In 

 the colder latitudes the never-failing verdure of this form of 

 trees cheers the desolate winter landscape, and tells to the 

 inhabitants of those regions that when snow and ice cover 

 the ground the inward life of plants, like the Promethean 

 fire, is never extinct upon our planet. 



Like mosses and lichens in our latitudes, and like orchideae 

 in the tropical zone, plants of the Pothos form ( 24 ) clothe 



