60 TROPICAL NATURE, AND OTHER ESSAYS. 



It is true that, as tliey are all low-growing herbs ^or 

 shrubs with delicate foliage, they might possibly be liable 

 to destruction by herbivorous animals, and might escape 

 by their singular power of suddenly collapsing before 

 the jaws opened to devour them. The fact that one 

 species has been naturalized as a weed over so wide an 

 area in the tropics, seems to show that it possesses some 

 advantage over the generality of tropical weeds. It is 

 however curious that, as most of the species are some- 

 what prickly, so easy and common a mode of protection 

 as the development of stronger spines should here have 

 failed ; and that its place should be supplied by so 

 singular a power as that of simulating death, in a manner 

 which suggests the possession of both sensation and 

 voluntary motion. 



Comparative Scarcity of Flowers. — It is a very 

 general opinion among inhabitants of our temperate 

 climes, that amid the luxuriant vegetation of the tropics 

 there must be a grand display of floral beauty ; and this 

 idea is supported by the number of large and showy 

 flowers cultivated in our hot-houses. The fact is, how- 

 ever, that in proportion as the general vegetation 

 becomes more luxuriant, flowers form a less and less 

 prominent feature ; and this rule applies not only to the 

 tropics but to the temperate and frigid zones. It is 

 amid the scanty vegetation of the higher mountains and 

 towards the limits of perpetual snow, that the alpine 

 flowers are most brilliant and conspicuous. Our own 

 meadows and pastures and hill-sides produce more gay 

 flowers than our woods and forests ; and, in the tropics, 

 it is in the parts where vegetation is less dense and 

 luxuriant that flowers most abound. In the damp and 



