SUMMARY. 
It is pointed out in this paper that many quantitative charac- 
ters of plants blend in Fi of crosses and exhibit a wide range of 
variation in F2, from which types like the parents — or perhaps 
even more extreme — and various intermediate forms can be 
isolated in F.^. Height of some plants is known to behave in 
this way. It is noted also that some quantitative characters, 
particularly height of several distinctly different plants, exhibit 
dominance instead of an intermediate condition in Fi, followed 
by a 3:1 segregation in F2 and simple Mendelian behavior in 
later generations. When pole and bush beans are crossed, 3:1 
segregation results whether the pole bean is very tall or only 
medium in height and whether the bush bean is very short or 
relatively tall. To determine the interrelation of these two 
types of behavior by an analysis of the factors concerned in 
height of plants in beans and by a study of their mode of in- 
heritance was the object of the investigations reported here. 
Mendel reported simple 3:1 segregation in F2 of crosses of 
tall and dwarf beans, both when the races concerned belonged 
to one species, Phaseolus vulgaris, and when one of them belonged 
to another species, P. multiflorus. The results of von Tschermak, 
with crosses between dwarf races of the former species and a 
tall race of the latter one, were by no means so simple as those 
reported by Mendel and were thought to be due in part at least 
to the action of more than one genetic factor. Results previously 
reported by the writer demonstrated simple Mendelian behavior in 
crosses between ''pole" and ''bush" habits of growth in Phaseo- 
lus vulgaris. 
The methods employed by the writer in making crosses, 
growing the plants, protecting them from cross-pollination by 
insects, making records, etc., as described in detail in the body 
of this paper, are believed to have been sufficiently careful to 
make the results reliable as a whole. 
Pole and bush beans are shown to differ in a single character, 
habit of growth. Bush beans are determinate in growth habit. 
The main axis is terminated by an inflorescence when from 
about four to eight internodes have developed and cannot be 
forced to make any further growth tho provided with the most 
favorable conditions of moisture and temperature, and even tho 
the flowers be removed to prevent the drain of seed production. 
Pole beans are indeterminate in growth habit. The first flower 
