THE TROPICAL ZONE. 77 



India Islands they grow in such numbers, that 

 their stems are as close to one another as the 

 slender firs and pines in our plantations. In 

 Australia and New Zealand they abound. In 

 that part of this zone which lies in South 

 America several interesting plants claim our 

 attention. One of the most beautiful is the 

 genus Ipomcea, a vast number of species of 

 which abound, especially in the woods, and 

 with their large and beautiful flowers, like those 

 of the convolvulus, of every variety of crimson, 

 scarlet, purple, violet, and other rich colours, 

 and their twining stems, forming rich festoons 

 from the trees and bushes, exhibit a most 

 gorgeous picture to the eye of the traveller. 

 One of the species yields the drug jalap ; 

 another (Ipomcea tuberosa) is in Jamaica an 

 evergreen plant, and as it will grow to an enor- 

 mous length, (three hundred feet,) and is pro- 

 fusely clothed with leaves and handsome yellow 

 fragrant flowers, it is often trained over lattice- 

 work and arbours, giving a delightful shade 

 and a refreshing perfume. 



The passion flower is another plant of which 

 numerous species inhabit South America and the 

 West Indies. In this, their native soil, they are 

 far larger than in our country, and very fragrant, 

 and climbing to the top of the highest trees, 

 (some of which are one hundred and fifty feet 

 high,) they twine about the branches, and clasp 

 them with their tendrils, while their blossoms, of 

 every shade of blue, red, white, or purple, hang 

 in profusion from them. The name of passion 

 7* 



