9 



ous. "Surface curnints due tu the wind, or other causes 

 crowd the pUntlets together in masses in which the relations 

 of the several individuals are incessantly changing." The 

 receptive stigmas must be puslied against the oider antliers, 

 through which tbty are pollinated. While there is in this 

 case an admirable adaptation for cross pollination, self- fer- 

 tilization may result wiien the pollen of the older stamen 

 drops on tlie stigma. 



FIG. 4, 

 Fig-. 4. (Pntamngeton crispiie)— Staminate flowers with debisoeing anthers 

 shown on the left. Pistillate flowers with large viscid stigmas on th'e right. 

 (After Kerner voB Marilaum.) 



Water Weed. 



Another interesting plant pollinated by 

 water is Elodea canadensis commonly found 

 in slow running streams and ponds northern United States. 



