78 



also been observed that tlic lateral Imds remain (Inriiiant until detached 

 from the parent conn, and that four year old bnds at the end of their 

 fonrth season are attachetl not to the corm but to the disorganizing cork 

 fragments at its base. 



An examination of the internal structure of mature corms at different 

 times in a growing season shows the following features. At the begin- 

 ning of growth in March the starch-filled parenchyma is a homogenous 

 mass. When the flowers and leaves are just above ground a lower region 

 of the jiarencliyma. corresponding to the four year old portion, shows signs 

 of softening, becoming more translucent and containing less starch. As 

 tlie season progresses tliis conditinn of cliangc increases until at or sodi 

 after the time of fertilizaticni of the flowers, there is little but disorgan- 

 ized parencliyma and scatteied vascular strands in the oldest portion. 

 Examination with the microscope at tliis time will show that a complete 

 separatory layer of phellogen has been formed so as to extend l)etweeri 

 the three and four year old portions, cutting off the older and protecting 

 the younger witii a layer of cork cells. 



The formation and growth of A. ti'i|i!iylluui corms is greatly intiu- 

 enccd li\ fdod and '-limat*". The vari;iti<.!i in size ol mature corms may 

 very probably he the direct i-esult of these inthiences. Certain it is that 

 soine corms lie dormant one year or longer and then grow vigorously 

 Then again conditions might require an extra amount of reserve food for 

 the jierfcction of fiuit in some uiifavoralile season and so sliort<'n tlie tim? 

 of some growth zones. In the majority of cases, barring very unusual con- 

 ditions, regardless of the number of years since the germination of the 

 seeds from which they sprung or since their separation as lateral buds 

 from mature corms, the underground stems of A. triphyllum are four 

 years old. 



