The Science of Plant Growing 



49 



simply ordinary leaves arrested at an early stage of growth, and have 

 the same arrangement as they. At the base of the individual flower 

 stalks in many plants are small leaves, termed bracts; in the Carnation 

 they come close up to the base of the calyx in two pairs. The bracts are 

 very numerous in the Marguerite, Cineraria, and other composites, and 

 closely surround each flower head, like overlapping scales. The bracts 

 surrounding the clusters of flowers of the Poinsettia are large and highly 

 coloured. 



Fig. 4U. Transmission of Water by Leaves towards circumference in (1) Calladium, and towards 



centre in (2) Khubarb 



The leaves of some plants, like the Sarracenia (fig. 41), Darlingtonia 

 (fig. 41), Nepenthes or Pitcher Plant (fig. 41), and Heliamphora nutans 

 undergo complete changes in appearance for special purposes, chiefly for 

 the purposes of catching insects and afterwards digesting and absorbing 

 them. In the case of the Sarracenia, Darlingtonia, and Heliamphora the 

 leaves roll themselves into a tube or trumpet, on the inner surface of 

 which a honey-like substance is secreted, and on which numerous sharp, 

 bayonet-like hairs point downwards. The insects, being attracted by the 

 honey, enter and feed till satisfied, but when they attempt to get out they 

 are repulsed by the bayonet-like hairs, and eventually sink back exhausted 

 and die. 



In the case of the Pitcher Plant (Nepenthes) the leaves are normal flat 

 expansions for a considerable length. The tissue on each side of the midrib 



VOL. I. 4 



