1893.] On the Development of the Caryopsis. 223 
already described. I am therefore compelled to dissent from 
Jumelle’s conclusions, which Van Tieghem has adopted in his 
voluminous treatise. 
The epidermis of the nucellus is seen in mature specimens: 
after treatment with potassic hydrate, but with well nigh 
obliterated lumina, fig. 13. 
Avena sativa L. 
At the time of flowering, the ovary of the oat differs in ap- 
pearance from that of the wheat chiefly in the more complete 
covering of hairs. As dévelopment proceeds, however, 
other and more fundamental differences appear. Owing to 
the assumption by the bracts of the protective function, the 
pericarp is thinner and more delicate than in the grains 
described above. Resorption of the ovary wall goes further 
appear. 
consist of 
interior ¢ 
a and the inner persists. It is very delicate, how- 
nd in the ripe fruit reveals its structure only upon treat- 
, includes only the layer external to this. 
Paid a “eg utricular covering. As growth from inside 
and in plana ent approaches this loose remnant, 
ly as in th ventually comes in contact, but never so 
i € wheat. Asa result, the pericarp is soldered 
: er points and is removed with less 
Plainly distin * €pidermis of the nucellus persists, but is 
Mite sushable only after treatment with potassic 
e : 
carehlly the si the Graminez were examined, but less 
Were in the Natu Se described above. The results obtained 
Peticarp and j hs of corroboration of the doctrine that the 
Megument unite in the fruit of the grasses. 
