132 GENERAL BOTANY 



are thus able to flow continually from the root cells to the bud 

 cells until the new stems and leaves are formed for the season. 

 When these are fully grown, the entire energy of the biennial 

 clover plant is devoted to the production of flowers, fruits, 

 and seeds. It is not necessary for us to trace the physiological 

 processes involved in the formation and maturing of these 

 structures, since they are exactly like those which have already 

 been recounted in the production of seed by the annual bean 

 plant. 



When the second season is ended, the biennial sweet clover 

 plant dies and, like the annual bean plant, intrusts to its seeds 

 the formation of new individuals with the opening of the next 

 growing season. It is thus seen that the storage root and buds 

 carry the plant over the first winter period of its biennial exist- 

 ence, while the seed with its reserve food and embryo is the part 

 which successfully endures the second winter. The advantages 

 and disadvantages of the biennial habit as exemplified in the 

 clover will be discussed in the summary following the outline 

 of the life of perennial plants. 



PERENNIALS 



The plant body in perennial plants continues its life from 

 year to year, varying in the length of its existence with the kind 

 of plant and the nature of the surroundings. Since the same 

 plant body continues to live through several seasons, we should 

 expect that perennial plants would manifest distinct adaptations 

 to seasonal changes which are not necessary in annuals and are 

 less marked in biennials. In discussing the life of perennials, 

 therefore, particular stress should be laid on those characteristics 

 which are connected with the perennial habit. 



The seasonal life of the herbaceous perennial for the first two 

 years is like that of the white sweet clover. The difference 

 between the two is that the roots and underground stems of the 

 perennial, when once, established, serve for storage and the pro- 

 duction of aerial shoots for many years instead of for the second 

 season only as in biennials. Many plants live from year to year 



