252 BOTANICAL GAZETTE [APRIL 
it was colored was proved by examination of material a day later, 
when many stained filaments could be seen. Beside this, the 
stain was taken up by the concave flanks of the ultimate placental 
branches which were stained very deeply, and which by their 
conductive action carried a large quantity of the reagent into the 
ovule, where it spread between the outer and inner integuments, 
but it was separated from the nearest portion of the egg apparatus 
by several layers of cells. Micropylar structures were stained but 
sparingly when the reagent was introduced into the bases of open- 
ing flowers as above. 
If, however, the injection was made on the day previous to the 
opening of the flower or earlier, the placental stalks were not 
stained so deeply, the amount introduced into the ovule being very 
small or mostly none at all. On the other hand, the inner integ- 
ument at the micropylar orifice was deeply stained, so that any 
pollen tube entering through this structure would certainly 
encounter the reagent. The conducting tissue on the inner ae 
face of the locule was deeply stained at this stage, and by bid 
action much of the color was conducted to the apical region 
through which the pollen tube must pass. 
It is to be seen, therefore, that the placental stalk presents 4 
concave flank most highly absorbent and conductive at the time 
that the egg apparatus is complete and awaiting fertilization. 
Before this time, the introduction of a reagent results in greater 
affection of the endostome and greater accumulation of the color- 
ing matter in the basal portion of the pistil through which the 
pollen tubes must pass. The probabilities would be greatly 1m 
favor of a reagent acting upon the pollen nucleus when introduce 
at this stage, to the total exclusion of any direct effect upon the 
embryo sac. Injections on the day of fertilization, at a 7 
when most of the successful operations were performed, resulte 
in some of the solution going into the ovular structures, but not 
into such close contiguity that the embryo sac might be supposed 
to be affected. In a few instances the endostome was also stained, 
while the tissue through which the pollen tubes pass into the locule 
accumulated the reagent. : 
Oenotheras were injected with methyl blue at the Desert 
