46 THE NATURE AND WORK OF PLANTS 



meadows in July and August, twining around the 

 stems of almost any herbaceous plant, forming 

 numerous coils of yellow or cream-colored flowers. 

 If the host plant is taken up and the nature of 

 the union between the two is examined, it will be 

 seen that the parasitic dodder sends a large number 

 of small blunt projections or knobs of tissue into 

 the stem of the host. These are the roots, and 

 they may arise at any point on the stem of the 

 dodder, and their function is the absorption of the 

 sap of the host plant. 



51. Method of germination and groiuth of the 

 dodder. — The seed of the dodder germinates on the 

 ground, sending up a long threadlike stem which 

 waves about slowly in the air until its tip comes in 

 contact with the stem of another species, when it 

 coils around it and sends out its roots. The roots 

 are seen to arise only at points where the parasite 

 touches the stem of the host. If the seed of the 

 dodder is planted in a pot with a young tomato 

 plant or castor oil plant, this may be observed. It 

 may be seen also that the only root formed at the 

 base of the stem on the germination of the seed is a 

 short peg-shaped structure, and that it simply holds 



