236 PRACTICAL COURSE IN BOTANY 
shown that the first step taken by the breeder to secure this 
result is to render the flower incapable of self-fertilization, 
342 
Fies. 341, 342,.— 
Unisexual flowers of wil- 
low: 341, staminate; 
342, pistillate. 
by removing the stamens. Nature ac- 
complishes the same purpose by the more 
effectual expedient of providing imper- 
fect, or unisexual flowers, in which sta- 
mens only, or pistils only, occur in the 
same flower. When the stamens alone 
are present, the flower is said to be stam- 
inate, or sterile, because it is incapable 
of producing seeds of its own, though its 
pollen is a necessary factor in seed pro- 
duction. If, on the other hand, the 
ovary is present and the stamens absent, 
the flower is pistillate and fertile; that is, capable of produc- 
ing fruit when impregnated with pollen. Sometimes both 
stamens and pistils are wanting, as 
in the showy corollas of the garden 
“snowball,” the hydrangea, and 
the rays of the sunflower. Such 
blossoms? are said to be neutral, 
from the Latin word neuter, mean- 
ing neither, because they have 
neither pistils nor stamens. They 
can, of course, have no direct part 
in the production of fruit, but are 
for show merely. (231.) 
268. Monecious and diccious 
plants.— When both kinds of 
flowers, staminate and _ pistillate, 
are borne on the same plant, as in 
the oak, pine, hickory, and most of 
our common forest trees, they are 
said to be monecious, a word which 
Fig. 343. — Twig of oak with 
both kinds of flowers: J, fertile 
flowers; s,s, staminate; u, pis- 
tillate flower, enlarged; b, verti- 
cal section of pistillate flower, 
enlarged ; c, portion of one of the 
sterile aments, enlarged, showing 
the clusters of stamens. 
means “belonging to one household”’; when borne on sepa- 
rate plants, as in the willow, sassafras, and black gum, they 
