DISCUSSION OF DEPENDENT PLANTS 



383 



351. Parasites. The dodders are the most familiar flowering 

 parasites. One of the commonest species is abundant in the 

 central and northeastern states, its thread-like, golden-yellow 

 stems forming great tangled masses on many kinds of plants, 

 from goldenrods to willows, growing in damp places. The 

 dodders and some root parasites, such as the beechdrops, 

 squawroot, and cancer-root (Orobanche, Fig. 309), are complete 





FIG. 309. Two plants of cancer-root (Orobanche) at left and middle of figure, 

 parasitic on the roots of a wormwood at the right 



parasites, and have no green foliage. Other plants, such as the 

 mistletoe, have green leaves and do photosynthetic work, but 

 depend on the host for water and the mineral substances dis- 

 solved in it. Such plants are called partial parasites. 



352. Development of parasite seedlings. The embryo of the 

 dodder is a thread-like object, which lies coiled in a spiral in 

 the endosperm of the seed. The seed germinates late in the 

 spring, and the seedling at first appears as a very slender, 

 naked stem, with a club-shaped lower extremity which is soon 



