STRUCTURE AND LIFE HISTORIES 
from the pouches, and snap over in, toward the center, 
thus dusting the insect with pollen, which is then trans- 
ferred to the stigma of the next flower visited by the 
insect. 
The corpse-plant, or Indian-pipe (Monotropa uniflora) , is 
of interest because, although belonging in a sympetalous 
FIG. 360. Milkweed (Asdepias sp.~). a, flower-bud; b, flower; c, 
very young pod; d, older pod in section, showing seeds; e, section of 
flower; /, top view of flower, showing the 5 hoods of the crown, each with 
a horn incurving to the stigma; between the horns are the cleft glands 
(shown enlarged at g), to which the pollinia are attached. 
family, it is polypetalous, and further because, living 
entirely as a saprophyte (or, possibly, as a root-parasite), it 
has entirely lost the power to make chlorophyll, and hence 
the power of photosynthesis (Fig. 230, p. 323). 
419. Milkweed Family (Asclepiadacese). The milk- 
weeds 1 present a most curious and interesting modifica- 
1 So called because they contain a milky juice or latex. 
