340 
STRUCTURE AND LIFE HISTORIES 
of one flowering plant on another (Fig. 246) . In some of 
these cases as, for example, the dodder (Cuscuta}, the para- 
site may have completely lost the power of elaborating 
chlorophyll, and thus lack the function of photosynthesis; 
FIG. 248. Dodder (Cuscuta s/>.), in flower. Parasitic on a golden rod 
(Solidago ulmifolia). (Photo by Elsie M. Kittredge.) 
the parasitism is then complete (Figs. 247, 248 and 249). 
In other cases the parasite may retain its chlorophyll- 
apparatus, and hence be only partly dependent upon 
the host, as in the case of the mistletoe (Fig. 250). 
Such plants are semi-parasites. Another example of 
