52 A LABORATORY MANUAL OF BOTANY 
how abundant pollen-grains are in these places mount a lit- 
tle of the surface of the soil and examine it. 
Why do isolated corn-stalks seldom ripen many good 
grains of corn? 
Account for the fact that popcorn and Indian corn 
growing near each other often become mixed. If the winds 
were from one direction during the season would the results 
be those usually found? 
Is wind, as an agent, favorable to the prevention of 
close-pollination? By a study of the various wind-polli- 
nated flowers at hand, determine how close-pollination is 
prevented in some of these plants. Is an open or closed 
flower best adapted to close-pollination? What kind of 
pollen is best suited to it? Do the plants studied have large 
amounts of pollen? Explain? 
Is all pollen from a given plant discharged at one time? 
Why? 
Do you notice any odor or brightly colored floral leaves 
in these wind-pollinated flowers ? 
Sketches of flowers and pollen-grains should be made to 
illustrate the points observed. ; 
LESSON XXVIII 
Reproduction—pollination and fertilization—pollination by 
means of insects 
Materials.—Flowers with tubular corollas, as: phlox, 
innocence, etc.; also of pea, bean, alfalfa, wistaria, sweet- 
flag, and mallow. 
Frequently the region about the school building will fur- 
nish plants that are better than some of those here men- 
tioned. 
Observation and study—A great many plants do not 
depend upon the wind as an agent of pollination, but so 
adapt their floral organs that this work may be done chiefly 
