II Pitcher Plants 35 



series. From this Genlisea has diverged in one direction, 

 Utricularia in another. That they have lost their roots is 

 not to be wondered at, for they are in great part aquatic 

 plants. Genlisea diverges but little from the hypothetical 

 ancestral form ; it has indeed very remarkable bladders, 

 but it retains the rosette of leaves seen in Pinguicula. 

 This is still represented in the terrestrial bladderworts, but 

 here there are most marvellous modifications of leaves 

 which obliterate the distinctions between leaf and shoot. 

 In the aquatic bladderworts the terminal floral axis of the 

 seedhng is suppressed, but there is still a rosette of leaves, 

 though often only in rudimentary form. The strength of 

 the development lies in the floating shoots, which are 

 homologous with leaves." 



Before we leave the pitcher-plants and bladderworts, we 

 shall simply notice another strange plant — the Scaly Tooth- 

 wort {Laih7'csa squainaria\ which is sometimes found in our 

 woods. It is a parasite on the roots of trees and shrubs, 

 and being without chlorophyll looks wan and strange. 

 We shall return to it in a subsequent chapter, but it is of 

 interest here to notice that its underground toothlike leaves 

 are not only solidly thickened stores for the food-reserve 

 appropriated from their hosts, but contain small hollow 

 traps in which many kinds of small terrestrial animals are 

 ensnared. The underground buds of Bartsia alpina show 

 a somewhat similar structure, and also imprison minute 

 animals. It is interesting also to note that these Bartsias 

 with some of their nearest allies, like the pretty euphrasy 

 and the curious yellow rattles and louseworts,i and one 

 or two others, are all parasites upon other plants as well, 

 their roots sucking those of grasses ; while through them, 

 as we shall see later, we pass to true parasites. 



^ Euphrasia officinalis, Rhinanthus Cf-ista- galli, Pediczilaris 

 sylvatica, and P. pahistris. 



