EMBRYOGENY OF ARISAEMA TRIPHYLLUM 



James Ellis Gow 



(with t^v-enty-four figures) 



This species is interesting as a representative of the lower monocoty- 

 ledons^ and as an extreme type of its family. If, as suggested by 

 Engler, those aroids which possess hermaphrodite flowers are to be 

 taken as the primitive type of the f amily, and the monoecious genera are 

 to be considered as reduced forms, Arisacma must be regarded as an 

 example of extreme reduction, since it is usually dioecious, Accord- 



clopment 



family 



be 



as having probably undergone a longer course of development than 

 they. But it seems quite as reasonable to suppose that the 



monoe 



primitive forms, and 



must 



Arisaema must take its place at the foot of the 1 



ferentiated form. If the former hypothesis be 



regard the occasional monoecism of this species as 



if the latter, it must be n 



accord with the general tendency of the family. It is plain, however, 



m cannot be 



monoecism 



classificat 



must be 



and even then the 



cannot be answered satisfactorily until 



the aroid genera have been worked out with far greater complete- 

 iS than has yet been done. 



The material here described w-as all gathered in the vicinity of 

 va City, Iowa, during the summer of 190 1, A part of it was worked 

 during the f ollow^ing Tvinter, but it was found necessary to drop the 

 rk, and die later phases were not undertaken until the present year- 

 ovaries were cut out one by one, or in groups of four or five, killed 



in parafBn to a thickness 



and fixed m i 



and stained with Delafield's hematoxvlin. H.-udexh 



Botanical Gazette, toI. 45] 



[3» 



