744 Hens low.— The Origin of Monocotyledons from Dicotyledons. 
characters have become hereditary, and are still retained in all Monocotyle¬ 
dons, whether they be aquatic or terrestrial, now. 
In the title of my first paper in 1892, I used the word ‘ Theory’, but 
judging from the very large amount of inductive evidence derived from Mor¬ 
phology and Microscopical Histology, coupled with the experimental 
verifications now recorded, I feel justified in abandoning the term ; for 
I would maintain that the conclusion has passed the stage of hypothesis 
and probability only, to that of a demonstrated fact. 
As a corollary it may be added that all the facts herein stated prove 
incontestably that the morphological and other characters, which constitute 
the classificatory distinctions between Dicotyledons and Monocotyledons, 
have all been acquired by the response of the ‘ soma ’—often long before 
any reproductive organs exist—to the aquatic conditions of life. Such are 
now permanent and hereditary. 
