100 The American Naturalist. [February, 
= readily to these considerations that they remained the only 
cases which were clearly elucidated: But it is hardly fair to 
dwell too strongly upon this point, for towards the close of the 
article, Mr. Clarke has expressly said: “ Here the question 
rises, why should there be a correspondence between the course 
of the flower seasons and the system of floral evolution? Solve 
this and the ‘ Philosophy of flower seasons’ is an open riddle.” 
Stated in this way, as a very interesting and important fact to 
be explained, I see little in the paper to which objection can 
be made. Otherwise, it might not unfairly be considered as 
an attempted refutation of the Darwinian flower theory, for 
what becomes of that theory if it can be shown that the time 
of blooming of insect-pollinated flowers is not ree with 
the time of flight of flower-loving insects? 
The object of this paper will be to attempt a preliminary 
contribution to the subject from the standpoint of data derived 
from the indigenous local flora near Carlinville, Illinois (lat. 
39° 21’), to test Mr. Clarke’s main proposition, to undertake to 
account for flower seasons asa result of the competition of 
plants for the services of various pollinating agencies, and 
those of insect-loving flowers as also correlated with the flight 
of flower-loving insects, and to attempt an explanation of the 
fact of the general preponderance of the most highly special- 
ized flowers in late summer. 
When a plant in a plastic condition succeeds in establishing 
itself in a highly favorable position, it throws off a number 
of closely allied forms which finally become more or less well 
marked incipient species. Asa result we find a number of 
nearly related forms in competition for a similar position in 
the soil,for a favorable position in the sunlight, and for the aid of 
the same pollinating agency. The process of producing similar 
forms may go on until the competition becomes so severe that 
it becomes disadvantageous. Then it becomes advantageous 
for some of the forms to avoid competition’ with the dominant 
group by migrating to a different region, or to a different kind 
1[n the interaction of organisms in the struggle for existence it strikes me 
that a law of avoidance of competition is more obvious than that of the survival 
of the fittest. 
