WEATHERWAX: MORPHOLOGY OF FLOWERS OF ZEA MAYS 139 
pollination and the production of well-filled ears, as is shown by 
a comparison of the ears from isolated plants with those that have 
been produced where a large number of plants near together 
were shedding pollen at the same time. 
hether or not cross pollination is necessary for the main- 
tenance of the full vigor of a strain is another question, and one 
that is by no means settled at present. It is not at all impossible 
that our different agricultural varieties will ultimately be found 
to differ in this respect. The maize varieties that we now have 
are the result of much haphazard hybridization, and nothing short 
of years of work will ever give conclusive results along this line. 
FLORAL ABNORMALITIES 
It has already been stated that monoecism is the rule, and that 
the male and female flowers are grouped together in separate 
inflorescences. But occasionally in probably all types, and often 
in at least one variety, some of the rudimentary organs are replaced 
by functional ones, and some usually functional are suppressed. 
As a result, organs of both sexes may be found in the same inflores- 
cence in any one of three ways or in a combination of these ways: 
1. Both sexes may occur in the same inflorescence but not 
necessarily in the same spikelet. 
2. Male and female organs may be found in the same spikelet 
but not necessarily in the same flower. 
3. The flowers may be perfect. 
The first type of sex combination is very commonly observed 
in nearly all varieties of corn. Many writers have mentioned it, 
and Montgomery (2), especially, has published a number of illus- 
trations of the phenomenon. Its occurrence in the tassel is 
apparently due to the development of the female instead of the 
male elements of the spikelets of one or more rachids or, more 
often, of the central spike. This produces a naked fructification 
resembling an ear, which Montgomery (2) makes the basis of his 
theory to account for the evolution of the ear. It has been noted 
also, as will be more fully discussed later, that some tassel spikelets 
in pod corn produce only female flowers. In the ear the flowers 
at the tip are often wholly staminate in structure, although they 
may never mature pollen. This transposition of sex in the ear 
