the Seed in the Alsinoideae. 
39 
fertilization (Fig. 1 6, per. /., Fig. 18 , per. 1 ). The growth of the embryo-sac 
takes place at the expense of the inner peripheral layers, which are 
successively absorbed, and a disorganized row of cells always surrounds 
the embryo-sac with the exception of a small concave area near the chalaza 
where the perisperm is developing. 
By constant periclinal and anticlinal divisions of the epidermal layer, 
the peripheral tissue keeps pace with the growth of the ovule, remaining 
about four or five layers thick. As the growth of the ovule becomes 
stationary, the meristematic activity of the epidermal layer relaxes (PL V> 
Fig. 19 } per. /.) until in the mature seed (PI. VI, Fig. 22, per. /.) the external 
layer alone survives. The cells of this layer increase in size and starch 
contents, but as their nuclei and cytoplasm remain active, they apparently 
retain the function of transitory starch storage tissue, which characterizes 
these peripheral layers from the fertilization stage. This epidermal layer 
in the seed persists till germination (Figs. 24 and 2 5, per. /.). 
Suspensor. The suspensor is filamentous, consisting of one large 
cell, and succeeded by a varying number of smaller cells in vertical 
succession, never less than four, generally five or six (PI. V, Figs. 14-18, sus.). 
The large basal cell (directed towards the micropyle) is formed immediately 
by the oospore, which elongates considerably after the fusion of the male 
and female nuclei (P'ig. 9, oospi). The resulting nucleus occupies the 
lower portion of the cell, surrounded by a dense reticulum. The upper 
portion’ then elongates, the cytoplasm becomes less dense, until in the 
extreme apex it completely loses its granular appearance and consists 
of a densely staining homogeneous substance (Fig. 9, hausi). The upper 
portion of the oospore in this plant elongates so much that it forms 
a haustorium at the micropylar end, which projects beyond the embryo-sac 
into the nucellar tissue. A certain compression is traceable in longitudinal 
section where the embryo-sac terminates (PL V, Figs. 9 and 15, hausi). In 
this tip the homogeneity of the contents remains distinct, and the wall 
is thicker in consistency. 
The process is similar in other species of the Alsinoideae, in which 
the suspensor is not prolonged beyond the embryo-sac. The oospore 
enlarges and forms the basal suspensor cell, but the apex remains rounder, 
though it stains darker than the rest of the cytoplasm (PL V, Figs, 10, 11, 
b. sus. c). The enlargement of the oospore occurs very quickly. After the 
first division of the oospore to form the primary suspensor a large vacuole 
appears, at the end of the basal cell (Figs. 10, 11, 14, 18), and the nucleus 
stations itself just below it. This position is characteristic and persistent. The 
contents of the basal cell are extremely dense, the chromatin .being lumped 
in the meshes of the reticulum. The nucleus is very large and active 
in appearance, and the cell suggests an absorbent organ. 
After the first divisions of the primary suspensor the synergidae appear 
