PART II.-EXPERIENCE IN OPEN AIR OR NATURAL CLIMATE. 



Chapter X. 

 STUDIES IN PHENOLOGY. 



Lender the general heading we shall consider, first, the wild plants 

 and their natural habits; second, the plants cultivated at experi- 

 ment stations under instructive experimental conditions, and, third, 

 the statistics of each and the experience of farmers in general from 

 a practical point of view. The study of the forest or natural habits 

 of plants leads us into the phenology of plant life. 



Phenology is a term first applied by Ch. IVIorren to that branch of 

 science which studies the periodic phenomena in the vegetable and 

 animal world in so far as they depend upon the climate of any 

 locality. Among the prominent students of this subject, one of the 

 most minute observers was Karl Fritsch, of Austria, who in his In- 

 structions (1859) gives some account of the literature of similar 

 works up to that date. He distinguishes the following epochs in the 

 lives of plants, and especially i-ecommends the observation of peren- 

 nial or forest trees that have remained undisturbed for at least sev- 

 eral years. His epochs are : 



(1) The first flower. 



(2) The first ripe fruit. 



The next important are, for the annuals: 



(3) The date of sowing. 



(4) The date of first visible sprouting. 



In order to assure greater precision he adds : 



(5) The first formation of spikes or ears. 



As Fritsch considers that the development of the plant so far as 

 its vegetative process is concerned depends princii)ally upon tempera- 

 ture and moisture, but that its reprodlictive process depends prin- 

 cipally upon the influence of direct sunlight, therefore he adds a 

 sixth epoch for trees and shrubs — viz: 



(0) The first unfolding of the leaf or the leaf bud or frondescence. 



This is the epoch when by the swelling of the buds a bright zone 

 is recognized which opens out and the green leaf issues foi-th. Cor- 



(Kh) 



