68 



FOUNDATIONS OF BIOLOGY 



parasitic species frequently grow into the tissues of the host, 

 and become more or less modified into suckers, or HAUSTOEIA. 



w 



FIG. 30. Dodder, a parasitic Flowering Plant, entwined about the stem of 

 its host, a Golden Rod. A, cross section of stem of host to show its penetra- 

 tion by the Dodder roots (haustoria). C, several Dodder seedlings growing in 

 the soil before attachment to a host, h, stem of host; I, scale-like.leaves; 

 r, haustoria; s, seedlings. (From Bergen and Davis.) 



In the Dodder and Mistletoe, the haustoria enter the tissues 

 of the stem of the host, while in many of the false Foxgloves 

 (Gerardia) they enter the tissues of the roots. In some 



