188 INTRODUCTION TO BOTANY 
the first successful investigator of the mode of inheritance in 
hybrids, was an Austrian monk, who carried on his researches 
in his monastery garden for eight years and published his 
results in 1865. His discovery was little noticed for about 
thirty-five years, when it quickly became generally known 
to biologists everywhere. Mendel’s law is not quite simple 
enough to be stated and illustrated in an elementary botany 
for secondary schools.1 
177. How hybrids are artificially produced. Hybridizing, or 
crossing, plants, is sometimes an easy, sometimes a rather diffi- 
cult, process. It is simplest in unisexual flowers — for exam- 
ple, in those of Indian corn. Here the tassel (fig. 126) is a 
Fie. 161. A few of the many leaf forms of different hybrids between the 
blackberry and the raspberry 
Modified after photograph by Burbank 
cluster of spikes of staminate flowers, and the ear (fig. 127) 
is a spike of pistillate flowers, each thread of the silk repre- 
senting a stigma and style attached to an ovary (grain of 
corn). In hybridizing corn it is only necessary to tie a paper 
bag over the ear before the silk appears, in order to keep off 
stray pollen, and leave it covered until full-grown, then re- 
move the bag, dust the silk thoroughly with pollen from 
tassels of the desired crossing variety of corn, and thereafter 
keep the ear covered until the silk is entirely withered. Some- 
times in hybridizing corn the stalks are detasseled just before 
the ears are ready to receive pollen. If all the stalks of one 
1See R. C. Punnett, Mendelism, The Macmillan Company, New York. 
Also L. H. Bailey, Plant-Breeding, The Macmillan Company, New York. 
