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The American Botanist 



VOL. XIV JOLIET, ILL., NOVEMBER, 1908 No. 4 



"These naked shoots, LIBRARY 



Barren as lances, among which the wind NEW YOR 



Makes wintry music, sighing as it goes, BOTANfCA 



Shall put their graceful foliage on again GARDEN. 



And more aspiring, and with ampler spread, 

 Shall boast new charms, and more than they have lost." 



— Cowper. 



T 



THE EVOLUTION OF A TUBER. 



BY WILLARD N. CLUTE. 



HE true sunflowers, members of the genus Hclianthus are 

 supposed to include both annual and perennial species, 

 but a very slight investigation is sufficient to show that there 

 are very few of the latter among them. It is tiaie that many 

 species, once planted, will continue to come up for years in- 

 stead of dying at the end of the season as the common sun- 

 flower of the gardens {Helianthns amiuiis) does, but the fact 

 remains that the plants which come up are no more the plant 

 originally planted than are the seedlings of the garden sun- 

 flower which may spring up in subsequent seasons. To be 

 considered a true perennial the same plant must live for several 

 successive seasons. The Solomon's seal, blod-root and tril- 

 lium are real perennials; the sunflowers only appear to be 

 ^ such because many of them have evolved special means for 

 carrying the life of the species over seasons unfavorable to 

 growth. The garden sunflower has but one way of surviving 

 the winter namely, by means of seeds in each of which is 

 snugly packed a miniature plant, while tlie parent plant dies 

 :nd is therefore an annual. 



