FRUIT BLOSSOMS 
409 
cycles and five pistils. The stigmas mature 
two or three days before the anthers, at 
which stage self-pollination is impossible. 
In the bud the stamens are bent inward, 
but gradually bend backward after the 
flower opens, the anthers on the outer row 
opening first. Self-pollination may occur 
by the styles finally bending backward un¬ 
til the stigmas touch the anthers, or in the 
case of flowers standing sidewise by the 
pollen falling on the stigmas. The quan¬ 
tity of nectar secreted within the concave 
receptacle is greatly affected by the weath¬ 
er; but sometimes it collects in large drops 
which overflow and fall to the ground. A 
great variety of insects, as honeybees, wild 
bees, wasps, flies, and beetles visit the flow¬ 
ers. Waite collected 50 and Mueller 30 
species. At Washington, D. C., Rochester, 
N. Y., and the Connecticut Experiment 
Station, the ground bees belonging to the 
genera Andrena and Halictus were found 
to outnumber all other insects. The writer 
observed a medium-sized pear tree in full 
bloom for an hour and a quarter, but dur¬ 
ing this time saw no insects except honey¬ 
bees, which were very abundant. A cluster 
of seven blossoms received eight visits in a 
quarter of an hour; and two other clusters 
consisting of 16 flowers received 16 visits. 
This was an average of a little more than 
four visits to each flower on the tree per 
hour. 
The great service rendered by insects in 
the pollination of pear blossoms is well il¬ 
lustrated by the experiments of V. H. Lowe 
at the Geneva Experiment Station, New 
York, in 1889. A number of small pear 
trees were covered with a hood of sheeting 
which came down over the tree like a bag, 
and was tied at the lower end around the 
trunk of the tree. On all the trees so cov¬ 
ered there was a large number of buds, and 
all the conditions were favorable for a 
good crop, except that the visits of insects 
were entirely prevented. As a result, on the 
whole lot of trees covered there was just 
one fruit. On another set of trees of the 
same sort and size, not covered, there were 
145 pears. In the case of another tree a 
large limb was enclosed in a bag with simi¬ 
lar results. 
Extensive experiments on the pollina¬ 
tion of Bartlett and Kieffer pears have 
also been made by Fletcher. Thirty thou¬ 
sand and eighty-one Bartlett blossoms, 
carefully deprived of their anthers and 
pollinated with Bartlett pollen, produced 
only six small fruits as compared with 763 
fruits produced by 7170 Bartlett flowers 
pollinated with Bartlett pollen, produced 
only six small fruits as. compared with 763 
fruits, produced by 7170 Bartlett flowers 
pollinated with Lawrence, Anjou, Dutch¬ 
ess, and, Kieffer. Two large 18-year-old 
Bartlett pear trees were completely cov¬ 
ered, just ^before the blossoms opened, 
with muslin sheeting in such a way that 
all insect visitors were excluded; but two 
limbs on each tree were permitted to pro¬ 
trude beyond the sheeting and were open to 
insect visits. These two limbs were loaded 
with fruit; while the flowers under the 
sheet, which were dependent on self-polli¬ 
nation, produced only 10 small pears. One 
thousand two hundred and sixty-eight Kief¬ 
fer pear blossoms pollinated with pollen of 
the same variety produced only five pears; 
while 2363 Ivieffer blossoms pollinated with 
Bartlett pollen produced 446 pears. Kief¬ 
fer is, therefore, almost completely self- 
sterile (Fletcher, S. W., “Pollination of 
Bartlett and Kieffer Pears/’ An. Rep. Ya. 
Poly. Inst. Agr. Exp. Sta., 1909-10). As 
in the case of the other fruits the impor¬ 
tance of honeybees, which can be import¬ 
ed, is clearly apparent. 
It was long believed that bees were act¬ 
ive in spreading fire blight; but more re¬ 
cent and careful observations show that 
the spores of this fungus are distributed 
by other agencies. See Fire Blight. 
THE POLLINATION OF THE APPLE. 
The apple is the most important of all 
fruits, and the value of the crop annually 
in the United States is at least $100,000,- 
000. Every orchardist should know what 
varieties are self-sterile and how they can 
be properly pollinated. Of 87 varieties of 
apples tested by Lewis and Vincent in Ore¬ 
gon 59 were found to be self-sterile; 15 
were self-fertile but gave better results 
when pollinated by some other variety; 
and 13 were partially self-sterile.* Among 
the self-sterile varieties were Bellflower, 
Gravenstein, King, Rhode Island Green- 
* The question whether a variety is sterile to its 
own pollen varies according to locality. For exam¬ 
ple, the bellflowers in the Pejario Valley, Calif., are 
self-fertile; elsewhere they appear to be self-sterile. 
