PHYSIOLOGICAL STIMULI AND ITS SIGNIFICANCE 230 
1 inflorescence with Yellow Hammer n. V. W.L. produced 90 seeds. 
d. The selfing of Yellow Hammer. 
a. 
+. 
Yellow Hammer n. V. W. L. pollinated autogamously and gei- 
tonogamously. The 5 bulbs of Yellow Hammer n. V. W.L. formed 
9 inflorescences which were pollinated thus, in the first half of 
April: 4 were selfed ; 3 with the pollen of Yellow Hammer abn. W ; 
1 with that of Yellow Hammer n. V. W. L.; of the 9th inflorescen- 
ce, the upper flowers were pollinated with Yellow Hammer abn. 
N.; of the lower flowers, which had been pollinated with Yellow 
Hammer abn. W., the ovary had increased visibly in size on the 
27th of April, but no good seeds were formed. One selfed inflores- 
cence gave 3 apparently good seeds. 
. Yellow Hammer n. N. pollinated autogamously and geitonoga- 
mously. Of the 11 inflorescences, formed by the 7 bulbs of Yellow 
Hammer n. N., 9 were selfed on April 4. In the case of two inflo- 
rescences, the perigonal tube and stamina were not cut off, and 
the pollination took place by pressing the pollen each time, by 
means of a clean brush, on to the stigma; of the 10th inflorescen- 
ce the flowers were not pollinated artificially, they remained en- 
closed in the parchment paper bag, all through flowering. 
Notwithstanding the fact that the flowers of this inflorescence 
and those of one of the 9 inflorescences mentioned first, had the 
ovaries considerably swollen, not a single seed was obtained. 
Yellow Hammer abn. N. autogamously and geitonogamously pol- 
linated. The 13 inflorescences, formed by the 10 bulbs of Yellow 
Hammer abn. N., were all selfed in the first half of April. As a 
rule, here also, the perigonal tube with the stamina was cut off. 
Of 10 inflorescences the flowers were pollinated autogamously ; 
one of these was produced by the plant, which had been forced 
into flowering in the hothouse; another plant was pollinated in 
such a way, that, proceeding from below upwards, the perigonal 
tube was removed of but half of the flowers, while the other flo- 
wers were pollinated by means of a brush, as described. The flo- 
wers of the other three inflorescences were pollinated geitonoga- 
mously, in such a way that the flowers of two inflorescences re- 
ceived pollen produced by the same inflorescence, while the flo- 
wers of one inflorescence were pollinated by pollen of other in- 
florescences. 
