II4 BOTANICAL GAZETTE 
‘Two weeks before pollination transverse sections of the stz 
the style show five strands of heavy-walled cells running from th 
angles of the central cavity half way to the periphery (jig. 34). 
tissue which these cells represent in cross section is four to six 
thick and runs the entire length of the stalk, being in the me 
line of the carpels. About the time of pollination these i 
cells are found to split into two layers, which separate in such a mé 
(jig. 35). The surface layer of cells on the interior of the 
becomes detached and undergoes partial degeneration. The 
conducting canals thus formed are continuous with the condu . 
tissue of the veins of the umbrella above, and open below midw 
between the main placental outgrowths. 
The stigmatic surface is richly provided with long, curt he: 
walled outgrowths of epidermal cells (fig. 31), which serve to ¢ 
pollen and hold it. Pollen was found to be present in abund 
on all stigmas examined. There is no definite sprouting- PS 
the grains, but the tubes grow more commonly from the meridio 
grooves. The pollen tubes grow between the cells of the stig 
of the conducting tissue along the vein of the umbrella and do’ 
the stalk of the style (fig. 30). 
The generative nucleus was not seen in any case to have div 
before the sprouting of the pollen tube, and the earliest positio 
which it was seen to have divided was in a tube which had n 
reached the center of the umbrella. The tube nucleus is spheri 
and precedes the generative nuclei. The latter are alike in form 
elongated and curved or often bent twice in serpentine ma 
The distance of the nuclei from the end of the tube is four t 
times the diameter of the tube. The cytoplasm is dense in the 
end and around the nuclei (fig. 36). 
When the pollen tubes enter the cavity of the ovary i 
five conducting tubes of the stalk, they are directly above the 
juncture of the two adjacent lateral placental outgrowths. 
course of the pollen tubes is at first a downward one bety 
outgrowths, and later an outward one radial to the axis of 
