POLLINATION REQUIREMENTS OF PLANTS* 
Fletcher, S. W. 
1941. Pollination. Standard cyclopedia of horticulture, by L. H. 
Bailey, v. 3, pp. 2734-2737. New York. 
p. 2734: ... it is well known that while the flowers of many 
plants may be readily fertilized by their own pollen, the offspring 
are stronger when pollen from another plant or another variety has 
had access to the flower. Sometimes pollen from a foreign variety is 
absolutely essential to the best fruit-formation. This is particularly 
true of certain varieties of the pear. A poor quality of fruit can 
be prevented only by growing together different varieties. Again, 
although a plant may readily pollinate itself, yet the pollen from 
another plant or variety may be prepotent over its own. This is to 
s a y » if the pla nt be P oll inated_ by ,its_own__pol len a leng_w ith. that_of a 
foreign variety, that of the foreign variety will usually effect ■'fer- 
tilization . 
pp. 2734-5: The flowers of insect-pollinated plants, on the 
other hand, are usually showy, and have nectar or fragrance, or both, 
pollen is more or less moist or sticky, so that it is not easily 
away... As the insect reaches &own for the nectar, which is near 
the bottom of the flower, some parts of its body are sure to become 
dusted with pollen.., Thus cross-pollination, or the transfer of pollen 
m the anthers of one flower to the pistil of another, is accom- 
plished. 
[Bees collecting pollen are just as valuable as those gathering 
In visiting large flowers they may be more effective, as they go 
directly to the reproductive organs.] 
The value of crossing to plants was first clearly proved by 
Charles Darwin in 1859. . . From the observations of Kolreuter, Sprengel, 
( ght, and his own exhaustive experiments, Darwin showed that con- 
tinu ed s elf-f srtiljzation is li kely to resul t in i nferior offspri ng;; 
while cross-fertilization, within certain limits, gives greater vigor 
to the offspring. Cross-fertilization between different flowers on 
the same plant usually has no appreciable advantage. 
p. 2736: In the selection of a pollinizer, several points must 
be considered: (1) The two sorts must blossom approximately at the 
same time in order that cross-pollination may be possible. The trans- 
fer of pollen from one variety to another is performed mainly by 
Insects. Waugh and Backhouse have shown that practically none of the 
pollen of the plum and other stone-fruits is carried by wind, it 
being moist and sticky. The same is true of pears, but apple pollen 
2 The underlining in the references does not appear in the original 
citations but has been added for emphasis. 
