188 BOTANY PART i 



Gephalotus, Sarracenia, Darlingtonia), the traps for the capture of 

 animal food are formed by the leaves which grow in the shape of 

 pitchers (Figs. 218, 219). The leaves of Nepenthes, for example, in 

 the course of adaptation to the performance of their special function, 

 have acquired the form of a pitcher with a lid which is closed in 

 young leaves, but eventually opens. The pitcher, as GOEBEL has 

 shown, arises as a modification of th'e leaf -blade. At the same time 

 the leaf-base becomes expanded into a leaf-like body, while the petiole 

 between the two parts sometimes fulfils the office of a tendril. These 

 trap-like receptacles are partially filled with a watery fluid excreted 

 from glands on their inner surfaces. Enticed by secretions of honey 

 to the rim of the pitcher (in the case of Nepenthes), and then slipping 

 on the extraordinarily smooth surface below the margin, or guided by 

 the downwardly-directed hairs, insects and other small animals fall 

 into the fluid. 



B. Heterotrophie Cormophytes ( 92 ) 



The green cbrmophytes utilise the light and by means of their 

 chlorophyll construct organic substance from carbon dioxide and 

 water ; they also require to transpire in order to accumulate the 

 nutrient salts from the soil in sufficient amount. Besides these forms 

 others, which obtain some or all of their organic substance directly 

 from the environment, are met with among cormophytes just as they 

 occur among the thalloid plants. They do not depend upon light 

 or transpiration, and frequently live at the expense of other living 

 organisms as PARASITES. The peculiar form of these plants and the 

 contrast they present to the green cormophytes are related to their 

 special mode of nutrition. From the changes in their external appear- 

 ance it is evident how far-reaching is the influence exercised by the 

 chlorophyll. With the diminution or complete disappearance of 

 chlorophyll, and consequent adoption of a dependent mode of life, 

 the development of large leaf -surf aces, so especially fitted for the 

 work of assimilation and transpiration, is discontinued. The leaves 

 shrink to insignificant scales, or are completely wanting. The stems 

 also are greatly reduced and, like the leaves, have a yellow instead 

 of a green colour. Since there is no active transpiration the roots 

 in many forms are reduced. Consequently the xylem portion of the 

 vascular bundle remains weak, and secondary wood is feebly developed. 

 In contrast to these processes of reduction resulting from a cessation 

 of assimilation, there is the newly-developed power in the case of 

 parasites to penetrate other living organisms and to deprive them of 

 their assimilated products. 



.Many exotic parasitic plants, especially the Eafflesiaceae, have 

 become so completely transformed by their parasitic mode of life that 

 they develop no apparent vegetative body at all, and do not show the 



