28 
Research Bulletin A T o. 2 
great care lias been exercised to prevent the entrance of imdesired 
pollen. After pollination each ear has been rebagged and a label 
tag attached to it. The experimental error in regard to pollina- 
tion is believed to be not greater on the average than about one 
seed per ear. (See East and Hayes 1.911.) 
The measurements of height of plant were made in the field. 
The main stalk of each plant was chosen for measurement and 
the distance from the surface of the ground to the top of the 
tassel determined. The number of nodes was determined by 
counting the leaves, except near the base of the stalk, where it 
was necessary to make a more careful examination. It is prob 
able that not all the basal nodes were noted, but any slight error 
of that sort is not serious, for, since all counts for the several 
families of any one series were made by one person, the same 
error would likely be made in case of each lot. The ears were 
measured after having been harvested and allowed to dry. Time 
of flowering was noted at approximately the same time each day. 
At each examination any plant whose stamina te flowers had 
begun to open was tagged with a label bearing the date and the 
individual number of the plant. 
The frequency distributions and the computations of statis- 
tical constants have all been checked over once, and, where 
practicable, this has been done by a second person. 
It is not claimed that no errors have been made in connection 
with the studies, but great care has been taken to avoid them and 
it is our belief that the data presented are essentially accurate. 
The plants of California pop and of Tom Thumb pop used in 
making crosses with Missouri dent and also the plants from 
which the later representatives of these varieties were grown 
were from seed obtained from seed dealers. The Missouri dent 
plants used in crossing and those from which all later lots of 
this variety came were from a single open-fertilized ear obtained 
from an exhibitor at the National Corn Exposition held at 
Omaha. Neither of these varieties, therefore, had been self 
pollinated before the experiments were begun. The other 
varieties used in these experiments were in most cases selfed for 
at least two generations before being crossed, but in some cases 
there were used parent ears obtained from commercial growe rs 
who made a specialty of the types furnished. In general, the 
descriptive notes below include only such characters of the several 
varieties as were made use of in the experiments reported in this 
paper. 
The strain of Tom Thumb used in the cross with Missouri dent 
is a very dwarf and very early pop corn. The plants tiller con- 
siderably and have short stalks with few nodes. The tillers are 
mostly shorter than the main stalk and frequently end in an ear 
