The Ohio Naturalist. 
[Vol. IX, No. 4, 
43 8 
they are usually falcate, widest at the extremity and cuneate 
at the base. After that length is reached they appear to grow 
more slowly and to broaden as well as lengthen till they are as 
long as ordinary laminae and have semicircular or subcordate 
bases (fig. 3). 
The diverse modes of origin of the two kinds of laminae 
emphasizes the importance of the dimorphism of the laminae. 
This was the character which caused Reinke (’03) to separate 
this plant from Lessonia and erect for it the genus Lessoniopsis. 
It is apparent that this is as valid a genus as any of the kelps. 
The origin of sporophylls in Lessoniopsis; about one-half natural size. 
These proliferated sporophylls give Lessoniopsis a very great 
interest from a phylogenetic point of view, for in them this plant 
shows the characters of both of the principal lines of development 
in the kelps. In the Lessoniatae branching is accomplished 
exclusively by the perforation of the meristem as in the sterile 
branches of this genus. In the Alariatae it is brought about 
altogether by proliferations from the transition region; these 
give evidence that they were originally restricted to reproductive 
functions as in this plant and that their further development 
