1 8 Campbell,— The Development of the Flower and 
Pollination. 
The large stigmatic papillae and the conducting-tissue of 
the style, which is a continuation of the same epidermal tissue 
whose cells form the stigmatic papillae, have much the same 
appearance. The dense granular cytoplasm and large nuclei 
indicate that it is a secretory tissue, and with little question 
these cells are mainly concerned in forming the substances 
which serve to nourish the pollen-tube on its way to the 
ovary. 
The ripe pollen-spore is nearly globular, and its finely 
reticulate exospore is ruptured by the pollen-tube (Fig. 34). 
The latter grows along the side of the papilla to which it is 
closely appressed. The growth of the pollen-tube through 
the conducting-tissue is not easily followed, and no especial 
study of this point was made, nor was the actual penetration 
of the pollen-tube into the ovule studied. There was nothing, 
however, to indicate anything peculiar in this respect. 
One of the synergidae is probably destroyed by the growth 
of the pollen-tube, but one of these can often be detected 
even after the first division of the embryo (Fig. 29 b, s). 
The Embryo. 
The development of the embryo was studied by Hieronymus, 
apparently with a good deal of care, and he gives numerous 
accurate figures of the different stages of development in his 
monograph. Unfortunately there is no account given in the 
text, nor is any explanation appended to the plates. On the 
whole his figures correspond closely to my own preparations. 
After the egg becomes invested with its cellulose membrane 
as a result of fertilization, it elongates and divides, as most 
other Monocotyledons, by a transverse wall into two cells, 
a basal suspensor-cell, in contact with the upper end of 
the embryo-sac, and a terminal embryo-cell, which projects 
