22 



ROOTS 



29. Parasitic roots. The dodder, the mistletoe, and a good 

 many other seed plants are called parasites, since they live, at 

 least in part, upon food which they steal from other plants 



FIG. 16. Dodder, a parasitic seed plant 



A, magnified section of stem penetrated by roots of dodder; B, dodder upon 

 a golden-rod stem ; C, seedling dodder plants growing in earth ; h, stem of 

 host; Z, scale-like leaves; r, sucking roots, or haustoria; s, seedlings. 

 A and C after Strasburger 



called their hosts. Parasites develop peculiar roots, which pene- 

 trate the tissues of the host and form most intimate connections 

 with the interior portions of the stem or root of the latter. 



