IN FLOWERING PLANTS. 173 
within the sac of the amnios, and that in other cases again, it 
is formed ‘‘ by a deposition of granular matter in the cells 
of the nucleus. In some of these cases the membrane of 
the amnios seems to be persistent, forming even in the ripe 
seed, a proper coat for the embryo, the original attachment 
of whose radicle to the apex of this Goat may also continue." 
Mr. Brown then alludes to this structure, as affording the 
best explanation of the structure of true Nymphzaces, 
Piperaceze, Saururus, and Scitaminez, in which the two al- 
bumens are of very different texture. Mr. Brown would ap- 
pear to be of opinion, that albumen may be formed in the 
nucleus without the persistence of the amnios, either as a 
membrane or as a sac filled with albumen. But it appears 
to me that in no instance in which the amnios is suffered to 
reach its ordinary amount of growth, is there a deposition 
of albumen in the cells of the nucleus itself. 
. M. Brongniart has entirely corroborated Mr. Brown's 
views respecting the above formation of albumen, but some of 
the instances he quotes in addition, will I believe, not be found 
to be so in reality. Graminez certainly are not, and if ana- 
logy, is allowed to guide us, Thesium also is not. M. Brong- 
niart proposes the term Perisperm for the albumen when 
. formed in the nucleus, and Endosperm when in the embryo- 
nary sac, a multiplication of terms as it appears to me totally 
unnecessary. 
M. Mirbel while agreeing with the correctness of Mr. 
Brown's views as given above, says, that although the albu- 
men often belongs to the nucleus or to the quintine, it 
belongs perhaps as often to the quartine ; that fourth enve- 
lope which neither Treviranus nor Mr: Brown have distin- 
guished. There is no doubt, but it is the quartine which 
` contains the albumen of the Tulip, of Tradescantia, and of 
Statice. It is again obvious that Mirbel has erred in sup- 
posing that his quintine is in all cases the amnios of Mr. 
Brown. 
The presence of albumen is the test of an imperfect evo- 
lution of the embryo, or rather of imperfect germinating 
powers: does this- explain why it is of such common occur- 
