and Fertilization in Oenothera . 
299 
These reactions show that the filiform apparatus is of cellulose. Then, 
aqueous solution of ruthenium red was tried ; the apparatus often remained 
entirely unstained, but sometimes it stained a pale pink or even a bright 
pink. This reaction indicates the occasional presence of pectic substance, 
which is against Habermann’s result (25), i. e. he denies the association of 
this substance in the filiform apparatus. 
Synergid and egg-cell . The cell wall of the synergid showed a cellulose 
reaction with Congo red and chlorzinc-iodide, and sometimes coexistence 
of pectic substance was clearly demonstrated by ruthenium red or methylene 
blue. As already stated, the distinct wall is differentiated around the upper 
two-thirds of the mature oosphere, though the remaining naked free end 
acquires the wall shortly after fertilization. The chemical nature of the 
wall is quite identical with that of the synergid. The lower naked end of 
the oosphere, as stated above, must be enclosed by the plasma membrane, 
which gave quite indifferent reactions to those reagents. 
Wall of pollen-tuhe. The apical portion of the pollen-tube, which was 
in contact with the egg apparatus, was carefully studied. The wall stained 
with Congo red, and a bright pink was obtained with ruthenium red or sky 
blue with methylene blue. These colouring reactions show the coexistence 
of cellulose and pectic substance. Removal of cellulose with cuprammonia 
was easily done, and the residual substance fully gave the pectic reaction ; 
but the removal of pectic substance by a weak base after the treatment with 
a weak solution of hydrochloric acid was entirely unsuccessful; moreover, 
the boiling method for the latter purpose was found quite inapplicable 
to the delicate section. It was often the case that, after the contents 
had been ejected, the wall of the apical portion of the pollen-tube was lined 
with some peculiar substance (PI. VII, Figs. 8 , 12 , m.s.; Text-fig. VII, 
1 , 3 , m.s.), which did not show any special colour reactions with Congo red 
or ruthenium red. As callose is commonly found in the upper part of the 
tube as the main component of the septa, treatments with corallin-soda, 
aniline blue, or sodium carbonate were applied to the substance in question, 
but it gave no callose reactions. For the control, leaves of Ficus containing 
cystoliths, stem of Benincasa and Cucumis for the callus on the sieve-plates, 
and pollen-tubes of The a japonica possessing callose septa were fixed and 
treated in the same way. The callose thus treated showed the same 
reaction as that in the fresh condition. Thus the nature of the lining 
substance under discussion was left undetermined, except that, judging from 
the position and general appearance, it may be a kind of mucilaginous 
substance which seals the opening and lines the apical wall. 
Self-sterile Hybrid between Oe. nutans and Oe. pycnocarpa . 
There were two forms of the hybrids between Oenothera nutans 
and Oe. pycnocarpa, when the materials were collected. One of the hybrids, 
