STERILITIES OF WILD AND CULTIVATED POTATOES. 3 
In the following year (1922) a comparison test for blooming was 
made as follows: Of 13 commercial varieties and of 2 promising seed- 
ling strains, 15 tubers each were selected from stock grown at Presque 
Isle. Each tuber was cut lengthwise in halves, which were numbered 
in duplicate and in series. One set was planted at Presque Isle and 
the other at the New York Botanical Garden. The Clio and Mclntyre 
varieties bloomed well at the botanical garden, but more abundantly 
at Presque Isle; Keeper, Sw T itez, and Seedling 24642 produced few 
flowers at the botanical garden, but bloomed abundantly at Presque 
Isle; Australian Blue. Early Ohio, Early Rose, Evergreen, Green 
Mountain, Hamakua, Irish Cobbler, Rural New Yorker, Triumph, 
and Seedling 40568 bloomed abundantly at Presque Isle, but not a 
flower opened at New York. In most cases the nonblooming plants 
produced flower buds, and in some cases these developed to the degree 
of showing the color of the corolla, but abscission occurred before the 
corollas expanded. 
The different results obtained from the plants grown from the two 
halves of tubers illustrate well the influence of environmental condi- 
tions on the blooming of any single variety. The different results 
obtained for different varieties grown in 1922 under the same condi- 
tions at the New York Botanical Garden also illustrate clearly the 
varietal differences in response to the same conditions in a single 
locality. 
That varieties of the potato may thrive and yield good crops of 
tubers under conditions that do not admit of flower production is in 
harmony with the well-known fact that species of plants may thrive 
beyond their range of natural blooming. It has long been recognized 
that the formation of reproductive organs in all sorts of plants is 
greatly influenced and often even determined by external and envi- 
ronmental influences such as light, temperature, and the kind and 
quantity of food. By controlling such conditions experimentally 
(see especially Klebs, 10, 11, 12, 13) many plants may be thrown into a 
relatively permanent vegetative condition. The influence of light and 
length of day on the blooming of plants has recently been emphasized 
by Garner and Allard (5). That such conditions may also exist in 
nature for certain zones in the distribution of plants has recently 
been shown by Setchell (20,-21). 
In widely extending the cultivation of the potato, the plant is now 
often grown under environmental conditions that do not admit of 
flower formation. The fruitlessness involved in the nonflowering 
habit and the abscission of flowers is to be regarded as a direct influ- 
ence of environment. It is an acquired or enforced sterilit} 7 . 
Whether the flowers when produced will be of one grade of intersex 
or another, or whether there will be physiological incompatibilities 
of one degree or another, or whether there may still be some other 
type of sterility is quite another question. 
^ In general, the potato is to be recognized as a cool-season crop. 
Nearly if not all varieties bloom in profuseness in the region about 
Presque Isle, Me., where the summers are cool and the growing sea- 
Bon is only about 100 days. But even here variations from season 
to season are in evidence. In such sections breeding from seed may 
well be undertaken. Farther south local conditions may in some 
sections favor blooming, or planting at a particular time may bring 
crops into development at a season which favors formation of flowers, 
