154 SAGACITY AND MORALITY OF PLANTS. 



browsing animals is called off them. When other 

 vegetable supplies have failed, and the Holl}-, being 

 an evergreen, attracts attention by its glossy green 

 leaves, the latter have been stiffened and protected by 

 the well-known prickles in the interval ! Southey's 

 familiar lines, therefore, are only partly true, although 

 they are remarkable in showing that he fully recog- 

 nised the reason for the defensive character of 

 Holly leaves : — 



" Below, a circling fence, its leaves are seen, 

 Wrinkled and keen ; 



No grazing cattle through their prickly round 

 Can reach to wound ; 



But as they grow where nothing is to fear, 

 Smooth and unarm'd the pointless leaves appear." 



Belt graphically describes a similar defensive kind 

 of vegetation existing in Central America. " In 

 the midst of these plains grow spiny Cactuses, low 

 leathery -leaved trees, slender, spiny Palms, prickly 

 Acacias, and thorny Bromelias. This spiny character 

 of vegetation seems to be characteristic of dry rocky 

 places, and tracts of country liable to great drought. 

 Probably it is as a protection from herbivorous 

 animals, to prevent them browsing upon the twigs 

 and small branches when vegetation is dried up." 

 Grant Allen, in commenting on the prickly char- 

 acter of the leaves of our common Saltwort {Salsola 

 kali), in Vignettes from Nature, goes, fully into the 

 matter. " Sand-loving plants are naturally exposed 



