Deep snow (10 inches plus) 



Spotty snow cover 



Snow appears 



Seed disseminated 



Seed being disseminated 



Seed ripe 



Shoot ond root growth rebeginning 



Seed In dough 



Seed in succulent stage 



Flowers in bloom 



Heods fully out 



Heads begin to show 



Flower stalks in evidence 



Snow disoppeoronce 



Root growth begins 



Shoot growth begins 



Frost out of ground 



Snow cover 



Jan I Feb I Mar I Apr I May I Jun I Jul I Aug I Sep I Oct I Nov I Dec I Jon I 



Chart 3. Phenological events in the annual growth of mountain bromegrass 

 {Bromus carinatus) in Ephraim Canyon, Wasatch Mountains, Utah, during 

 the four years: (A) 1932; (B) 1933; (C) 1934; (D) 1935. (After McCarty, E. C. 

 (138A), "The Relation of Growth to the Varying Carbohydrate Content in 

 Mountain Brome," Figure 3, U. S. Dept. Agric. Tech. Bull, No. 598, 1-24 

 (1938).) 



these processes, such as formation of leaves, elongation of shoots, 

 appearance of flowers, and dissemination of seeds (see Chart 3). 

 Periodicity results from inherent genetic characteristics of each 

 species under the influence of a particular combination of en- 

 vironmental conditions. Periodicity means particularly the re- 

 currence at certain times of these processes and their manifesta- 

 tions, while phenology refers more to the appearance of the 

 manifestations at certain seasons of the year (Figure 3-2), rather 

 than to their cyclic nature. Aspection is the appearance or 

 aspect of the community as a whole at different seasons. Perio- 

 dicity is a strongly fixed character in plants, for even in portions 

 of the Tropics where great uniformity in climate prevails, it is ap- 

 parent in the fall of leaves at certain intervals and also in periods 

 of intensive growth followed by dormancy. 



Periodicity is not readily altered even though climatic condi- 

 tions change. Correspondence in climatic and life-cycle periodic- 

 ities indicates the location of the native home of a plant, whereas 



86 • Xke Conrnmimxaity 



