86 James Small on 



and Centropogon, which are relatives of the little blue Lobelia 

 of herbaceous borders and Avindow-boxes. 



About this time a great uplifting movement began which 

 ultimately gave rise to the Andes and, later on, to the Rocky 

 Mountains. This new range of mountains abutting on the 

 tropical forests of the Amazons presented an entirely new habitat, 

 which was open to colonisation by such of the forest species as 

 could survive the change from a rich, warm, moist environment 

 to the more or less arid conditions of the mountain side. 



The Lobelioid climbers were amongst the early coloin"sts ; 

 descending the trees, or rather failing to find trees upon which to 

 climb, they first became scramblers on the low bushes of the 

 forest edge. Then as they spread year by year up the hillside 

 beyond the tree-limit to beyond the limit for bushes, they became 

 ground-growing scramblers. The severe conditions reacted upon 

 these pioneers, producing stunted growth and general crowding 

 together of all parts of the plant. The stems being short, the 

 leaves were crowded ; the flower-stalks being short or altogether 

 absent the flowers became crowded. The general tendencies 

 towards the production of such characters as hairy appendages to 

 the style branches, tails and apical appendages to the anthers, a 

 few ovules or only one ovule in each ovary, etc., became expressed 

 more fully in the flowers, and since these were already grouped 

 in dense clusters, something very like the flower-head of a Com- 

 posite was the result. 



The young flowers being protected by the green leaves 

 surrounding the flower-head, the calyx became useless, and 

 disappeared at an early stage. The windy arid conditions on the 

 hillside caused the development of hairs on most parts of the 

 plants, and the hairs on the top of the young fruits grew longer 

 than those lower down on the fruit. In this way there was 

 formed the pappus, which proved very useful. The hairs, 

 developed in response to the dry windy conditions, when organised 

 as a fringe on the top of the fruit, became more than protective. 

 They caught the wind, more or less like an expanded umbrella ; 



