- 31 - 
p. 266: The presence of honey bees materially aided in setting 
heavy crops on the following combinations of varieties: Formosa and 
Wickson; Eeauty and Santa Rosa; Diamond and Grand Duke. Observations, 
furthermore, showed that many other combinations were also benefited 
by these insects. 
Hendrickson, A. H. 
1919. Plum pollination. Calif. Agr. Expt. Sta. Bui. 310, pp. 1-28. 
p. 27: A comparison over a number of years between trees where 
there was an abundance of bees flying and trees where bees were 
scarce, emphasized the desirability of having bees in the orchard. 
Even self-fertile varieties were immensely benefited by the presence 
of bees as an agency for distributing pollen . 
Kinman, C. F. 
1931- Plum and prune growing in the Pacific States. U. S. Dept. Agr. 
Farmers' Bui. 1372, 57 pp. 
p. 25: The presence of bees in the plum orchard at blossoming 
time has been demonstrated to be almost an economic necessity.... 
Poor crops or perhaps failures may be expected of self-sterile 
varieties where no bees are present, and even with self -fertile 
varieties the presence of bees has caused a decided increase in 
the crop . 
Strawberry 
Darrow, G. 14. 
1937. Strawberry improvement. U. S. Dept. Agr; Yearbook 1937: 445-495 • 
p. 455: Pollen is carried by bees and other insects, but it is 
also thrown out of the stamens as the anthers crack open ... or it 
is jarred out and blown by the wind and falls on the pistils. A 
variety having perfect or hermaphrodite flowers can produce fruit 
when planted by itself, but one with pistillate flowers cannot set 
fruit unless perfect-flowered plants are nearby to furnish pollen 
through the agency of bees or other insects . 
Robbins, W. W. 
1931. The botany of crop plants. Ed. 3, 608 pp. Philadelphia. 
p. 347: Fertilization and Development of the Fruit. — Strawberries 
are protogynous, that is, the pistils of a flower mature before its 
stamens. Hence cross-fertilization is secured; and this usually by 
insects. Non-fertilization or incomplete fertilization is usually 
indicated by berries with hard, greenish, undeveloped apices, so-called 
"nubbins." 
Tung. See Almond. 
