214 The Botanical Gazette. 
Introductory. 
The question involved in these discussions is one of some 
importance. The existence of the caryopsis asa type of fruit 4 
distinct from the achene has not been challenged, so faras] _ 
have been able to learn, until 1888 by Jumelle in the above — 
cited articles. The adoption of his view and the incorpora — 
tion of it into so important a treatise as that of Van Tieghem — 
is likely to lead to confusion. To determine whether the — 
earlier and accepted view or that of Jumelle is correct has 
been the object of this investigation. d 
To this end a careful study.has been made of the history 
of every part concerned from the time of the fertilizationol 
the ovule to that of the complete ripening of the seed inthe — 
corn (Zea Mays L.), wheat (Triticum vulgare Vill.), and 
the oat (Avena sativa L.). As the developmental history — 
of the fruit of the corn has received less attention heretofore q 
than that of the other common cereals, I have described it 4 
with some detail. The wheat and oat receive briefer mention — 
The grains used were collected from fields near Baraboo, — 
Wis., during the summer and fall of 1890. The matena — 
used was gathered at suitable stages of development from — 
plants of typical growth, and while fresh was immersed! — 
from twelve to twenty-four hours, according to its bulk, @ 
solution of chrom-acetic acid. The following proportions by 
volume were used: saturated solution of chromic acid, 
parts; acetic acid, 7 parts; rain water, 990 parts. 
more rapid and complete penetration of the tissues © 
corn to take place, the young axes were cut intos 
From the acid the material was transferred to wea 
after the removal of the surplus acid by thorough and repea’s 
washing in rain water. After gradual hardening in 
microtome. Older grains were cut free hand. «ay gnuch 
potassic hydrate was found advantageous in studying 
compressed tissues to swell them. 
Zea Mays L. ae 
At the time of the maturation of the egs ae perpet 
ovary is unsymmetrical in form, being bent from e, or sil 
dicular in such a manner as to cause the long style, 
