1892.] Botany. 703 
BOTANY. 
Development of the Ovule in Grindelia squarrosa.—The 
ovule in Grindelia arises by tangential division of the cells of the first, 
second and perhaps third hypodermal layers, resulting in an up-push- 
ing of the floor of the ovarian cavity (figs. 1-4). As Coulter’ says of 
Taraxacum, the ovule does not appear exactly at the bottom of the 
cavity of the ovary, but a little at one side. The ovule springs from 
the axis of the flower as is shown by the passing of the fibrovascular 
bundle directly from the axis to the funiculus. In this respect Grindelia 
agrees with Helianthus (figs. 16 and 17) and differs from Taraxacum 
in which, according to Coulter, the fibrovascular threads of the funi- 
culus come from a carpellary branch of the axis. The young ovule 
early begins to curve upon itself, the single integument appears on the 
upper convex surface and, by growth beyond and around, completely 
enwraps the apex of the ovule, the nucellus (figs, 5-7). At this time 
we distinguish three portions of the ovule—funiculus, integument and 
nucellus. The nucellus consists of an axial row of cells covered by 
the epidermis. In the apex of the nucellus, immediately beneath 
the epidermis, is the archesporium (figs. 5 and 6). This divides into 
two and then four cells (figs. 7 and 8). By accelerated growth the 
most deeply situated of these cells absorbs or pushes the others toward 
the apex of the nucellus and becomes the embryo-sac (figs. 9-11). At 
the same time the epidermis of the nucellus shrinks and disap- 
pears. Concomitant with the degeneration of the nucellar epidermis 
the adjacent layer of the integument becomes greatly modified, form- 
ing what Hegelmaier’ terms the “ Endodermis.” Its cells lengthen 
radially, and the cell walls become much thickened and resistant to 
the section knife. Of the stages between the embryo-sac with but one 
nucleus and the mature state of the same I have found few represen- 
tatives. Enough was seen, however, to indicate that the typical order 
is followed (figs. 12-14). The nucleus undergoes a three-fold division. 
A tetrad is seen in the micropylar end. The usual number of the 
antipddal cells is two (fig. 13), though rarely a third is seen (fig. 14). 
They are situated in a linear series with the embryo-sac, being early 
1Development of a Dandelion Flower, AMERICAN NATURALIST, Vol. xvii, No. 12,” 
Dec., 1883. 
Uber den Keimsack einigen Compositen und dessen Umbiillung. Bot. Zeitung. 
Nos. 50-52, 1889. 
