BEHAVIOR OF THE PoLLEN TuBE 89 
elements of the ovarial partition.fuse at their point of meeting and 
so complete the separation of the originally single ovarial chamber 
into locules. 
HISTOLOGY 
When the parts above described are young, the cells are, of 
course, uniformly isodiametric. After all the primordia are laid 
down, and the period of rapid growth prior to the assumption of 
the definitive form sets in, the relative rapidity of growth of the 
several organs is accompanied by changes in the proportions of the 
component cells. At about the time of fertilization the histolog- 
ical features are as follows. i 
The basal element of the ovarial partition consist of thin-walled 
parenchyma whose elements are slightly elongated in the direc- 
tion of the flower axis and contain the vascular tissue which sup- 
plies the ovules. Where the stylar portion of the partition abuts 
against the basal elements, the cells of the latter are flattened out 
transversely, this being due partly to the pressure and partly to the 
mode of growth. The epidermis of the basal element of the par- 
tition has, at this point, very much thickened walls. The thicken- 
ing commences in the outer walls (fig. 7) and extends at the 
period of fertilization to the lateral, but not to the basal walls 
(fig. 5). At the same time the regularity of the layer of cells is 
lost in the process of fusion which takes place between the basal 
and the stylar elements of the partition. 
The stylar portion of the partition is composed at the time of 
fertilization of three distinct tissues. The innermost of these, or 
that lying in the axis of the compound style, and that with which 
we are here concerned constitutes a conductive tissue and is com- 
posed of elongated narrow cells with transverse or slightly oblique 
end walls and no intercellular spaces. These cells may be further 
distinguished from the surrounding tissues by their denser cyto- 
plasmic content, and thicker, more deeply staining walls. Capus 
(2) has noted that the cells of the conductive tissue in the plants 
studied by him have thickened walls (collenchyma), but in Glche- 
milla arvensis according to Murbeck (10) no such thickening 1s 
present in any part of the course of the conducting tissue, a con- 
dition which is found in the free portion of the style of the-plants 
under consideration. Here the cells are longer than in the stylar 
