beans, on the other hand, generally practice self-fertilization , 
each plant having only one parent. The flowers of corn are 
generally imperfect, i. t\, the male (staminate) and female 
(pistillate) are not borne in the same dower. The former are 
produced at the apex of the plant in the tassel, while the latter 
occur on the ear. Each little immature grain of corn has a long 
“silk” attached to its outer face, the two structures togethercon- 
stituting the pistil of a single female (lower. When the silk has 
extruded itself from the husk for some distance, a fine dust 
(pollen) from the tassel falls upon it (pollination l and fertiliza- 
tion follows, the end result being a corn grain, containing an 
embryo corn plant. The details of the process are much more 
complicated than may be inferred from this brief description. 
Peas and beans, in contrast to corn, have perfect flowers, /'. e ., 
the male and female structures occur together, and in such a 
position in reference to each other that the pistil is usually 
dusted with pollen from its own flower. This eventually brings 
about self-fertilization. 
In comparing these two methods of fertilization, the impor- 
tant point to be noted is the opportunity a corn plant has for 
inheriting characteristics from two different parents rather than 
from only one, as in the pea. In this we have the explanation of 
the difference between the fields of corn and of peas. In the one 
field, through cross-fertilization, manv new types of plants may 
be produced, while in the other, all the plants will have the char- 
acters of their one parent. Contrasting the two fields frcm the 
standpoint of vigor, one cannot appreciate the fact that the 
inbred pea is less robust that the cross-bred corn. Yet when two 
diverse strains of peas are crossed, their first generation progeny 
show’ a marked increase in vigor, in comparison with which an 
ordinary variety of pea w r ould appear to be degenerate. 
Through artificial self-fertilization, pure strains of maize 
have been isolated, some of which produce rental 1, ably well even 
after many generations of inbreeding. Other strains isolated 
from the same stock yield only “nubbins”; while still others are 
very rich in the production of sterile plants, some of which barely 
retain enough vitality to mature (Fig. 3). After a pure race has 
been isolated, the degenerative tendency ceases, and the strain 
