The Determinative Action of Environic Factors Upon Neobeckia acquatica Greene. 269 



and stem, which are formed in terrestrial cultures- These fusiform 

 structures were cut into two parts by a single transverse section. The 

 uppermost part bearing the active crown and other buds produced leaves 

 of the broader type, but the smaller lower part, which was not so 

 heavily stored with surplus food material and which had only axillary 

 buds, in eveiy case displayed nepionic leaves of the extremely narrow 

 type. 



The growth of cuttings consisting of a portion of stem in water, 

 from plants cultivated in the soil was marked by curvatures probably 



Pig. 7, 



Fig, 9. 



Fig, 7. Rejuvenating lateral bud of Neobeckia 

 attached to stem with narrow nepionic leaves. 



Fig, 8, Cutting from a stem of Neobecbia grown 



in water. 



Fig. 9, Longitudinal section of segment of 



aquatic leaf of Neobeckia. 



Fig. 8. 



induced by iilumination, and the terminal part formed a number of 

 short internodes homologous with those of a submerged rosette, during 

 the winter season in New York when the total illumination was low. 

 With the advent of spring the formation of finely divided leaves began 

 (Fig. 8), which might be considered as corresponding to those of the 

 free stem of a plant rooted in the mud. The examination of these 

 leaves showed the familiar structure of hydrophytes. The smaller sub- 



Flora, Bd. IOC. 



18 



