40 Gibbs. — Notes on the Development and Structure of 
contracted and empty and are not traceable further, owing to the rapid 
aggregation of nuclei and dense cytoplasm at this portion of the em- 
bryo-sac. 
The fan-like arrangement of the cell rows at the apex of the nucellus 
indicates a convergence towards a given point (Figs. 16-18, ap. nuc.), and 
moreover these cells show disintegration in proximity to the base of the 
suspensor, and they are arranged with their long axes directed towards 
it. As the embryo grows the basal suspensor cell elongates (PL V, Fig. 19, b. 
sus . c.) and the contents become less dense and more granular, until finally, 
as the cotyledons develop and the organization of the endosperm cap 
follows, the suspensor is completely re-absorbed by the latter (Fig. 21, dis. 
sus . c). The basal cell of the suspensor would thus form the first sucking 
organ, but, as the wants of the embryo increase, it is replaced by the 
endosperm cap, with its more complex organization and advantageous 
position, with regard to actual and potential food supply. 
In the Alsinoideae a complete series is obtained in the grades of or- 
ganization of the basal suspensor cell. In the Alsineae it reaches its 
greatest development, and in Si ell aria media the climax may be said 
to occur. In the Sperguleae it is so reduced as to be hardly differentiated 
from the rest of the cells of the filament. The importance of this cell 
is indicated by its complex organization before the first division of the 
oospore (Fig. 9, oosp.). 
Most work on the subject seems to point to the fact that the suspensor 
where it occurs is an absorbent organ. It may produce vermiform haustoria 
which seek available sources of food supply, as Treub ( 13 ) first described 
for orchids, or it may consist of large swollen cells charged with nutritive 
material, as in some Leguminosae (Guignard, 17 ). In the Alsineae the 
suspensor is very small if we exclude the first cell, consisting of only 
one row of three or four cells. In the Sperguleae it is more massive, 
and the cells divide again to form a double row ; so that possibly the 
formation of the large basal cell, where it occurs, is to reinforce the ab- 
sorbent power of the suspensor as a whole, just as the peculiar development 
of the micropylar and absorbent portion of this cell in Stellar ia media 
suggests an attempt to increase the area of available food supply. 
The inner integument. The integuments each consist, as has already 
been explained, of two layers of cells, forming four layers in all, of which 
three only persist in the ripe seed. These layers are at first undifferentiated 
in the case of each integument (Fig. 6, o. i., i. if In the inner integument 
which arises first the cells at the apex increase in size as it closes over 
the nucellus, and these cells project far beyond the outer integument 
(Fig. 6 , i. i). Before fertilization they stain rather darkly (Fig. 7, i. i.), 
and after the passage of the pollen-tube they lose contents and shrink 
in size often leaving quite a cavity in which the tube persists. They 
