760 H. E. KNow.ton 
Von Planta (1885) found 14 per cent of cane sugar in Corylus pollen and 
11 per cent in Pinus pollen. Mangin (1886) noted that Betula and certain 
Coniferae pollens have reserve starch, while others (Narcissus) have 
stored sugar only. Green (1894) stated that many species of pollen 
contain starch, glucose, maltose, and cane sugar. In the immature pollen 
grains of wheat, Eckerson (1917) at first found glucose, and later, starch 
appeared. Martin and Yocum (1918) state that, at pollination time, 
apple pollen contains proteins and small amounts of sugar. According 
to Green (1894) and others, these organic reserves are broken down by 
appropriate enzymes during the germination of the pollen. 
Determinations show a surprisingly small water content, only 10 to 20 
per cent being present. The amount varies under different conditions 
and in different seasons. 
Pollen of corn (Zea Mays L.) 
Corn pollen is produced in large quantities. This fact was one of the 
reasons for its selection as a material for testing in these experiments. 
Under favorable conditions, in the early morning, it was very easy to 
collect from 25 to 30 grams of pollen in a cornfield. This allowed analyses 
to be made, which could not have been done with the more scanty pollen 
of other species. Corn pollen seems very dry, does not adhere, and is 
consequently wind-borne. 
Fresh corn pollen is oval to round in shape, altho elongated grains are 
often noticed. On exposure, they become shrunken. Corn pollen is larger 
than Antirrhinum, measuring 1064 by 120u. When the microscope is 
properly focused, circular germ pores, one to three in number, can be 
seen. These pores resemble bordered pits of wood tissue. 
Unlike Antirrhinum pollen, starch is the storage carbohydrate of corn 
pollen, whole pollen grains often staining a deep blue in iodine solution. 
Other grains did not stain so deeply, indicating that they contained less 
starch. Chemical analyses showed about 10 to 15 per cent starch, 
expressed in percentage of fresh substance. The table given by Andronescu 
(1915) shows 39 per cent of total carbohydrates. No starch analyses 
were made by him. 
Altho corn pollen is wind-borne and seemingly dry. the moisture content 
is very high. Determinations made by the writer showed that it ranged 
from 50 to 65 per cent, depending on the amount of moisture in the air, 
