416 LUSSOIfS WITS PLANTS 



approach of winter ; to determine the features of the 

 winter epoch ; to determine the fleeting or fugitive 

 epochs of the year. 



528a. It is evident that any miscellaneous set of notes will satisfy 

 none of these purposes, unless, possibly, the last. Such plants must be 

 selected as will give unequivocal periods, and which are convenient for 

 observation year by year. The observer must feel that records are 

 valuable in proportion to the number of years over which they extend. 

 Except in determining fugitive epochs, observations of a single 

 season alone have little value. For full instructions upon the taking of 

 phenological observations, see Bailey in Monthly Weather Review of 

 the United States Weather Bureau, September, 1896. 



5286. Five tests of good phenological observations are as follows : 



1. As broad a distribution as possible of the plant selected 

 for observation. 



2. Ease and certainty of identifying the definite phases which are 

 to be observed. 



3. The utility of the observations as regards biological questions, 

 such as the vegetative periods, time of ripening, etc. 



4. Representation of the entire period of vegetation. 



5. Consideration of those species which are found in almost all 

 published observations, and especially of those whose development is 

 not influenced by momentary or accidental circumstances, as the 

 dandelion is. 



529. There are four epochs which are most im- 

 portant in taking phenological notes ; upper surface 

 of leaf first showing ; first flower open ; first fruit 

 ripe or full colored; half or more of the leaves full 

 colored. If, however, one desires to record only 

 the opening of spring in the various years, only the 

 first two events may be noted. In rural communi- 

 ties, the dates of planting and harvesting of the 



