THE AMERICAN BOTANIST. 
Ill 
nectar glands in the petioles of the cotton leaf as an 
attraction to ants which serve to protect the plant from 
the boll weevil and other injurious insects has recently 
awakened great interest and has been turned to economic 
account. 
POLLEN. 
If we examine the flowers of any plant, it matters not 
of what description, provided it be a true flowering plant, 
we shall find associated with them, either as a powder or, 
as in the orchids, in a somewhat viscous mass, an immense 
number of small grains which represent the pollen, i. e., 
the male or fertilizing element. In some cases, however, 
where the male and female flowers are separate, we must, 
of course, only look to the former for this powder, while 
the latter we shall find, as a rule, to be comparatively 
inconspicuous. Thus in many of the Nut tribe we find the 
male flowers associated in conspicuous catkins, accom- 
panied by an abundance of pollen, this abundance being 
necessary in order to secure the fertilization of the distant 
female flowers by the aid of the wind, insect agency being 
largely debarred owing to the absence of suflficiently obvi- 
ous flowers fitted to attract them. 
These grains, despite their minuteness, are very beauti- 
ful objects under the microscope, and will repay examina- 
tion, as they will be found to var^^ very greatly in size, 
shape, make, and color, every species of flower having its 
own distinguishing type. Their size would appear to be 
correlaUd with the length of the stigma, or stalk, of the 
female flower, so that in the lilies and evening primroses, 
to take familiar examples, we shall find them of compara- 
tively large size, while in short-stigmated flowers they are 
much smaller. The brilliant carmine or orange -tinted 
pollen grains of the lilies are especially beautiful objects, 
even under an ordinary lens. 
The reason of this correlation is a very simple one. 
When the pollen grain is conveyed either b3^ wind, insect, 
or other agency to the stigma of the female flower, or 
