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or nearly self-sterile, and those of the Pacific coast have male 
and female organs on separate plants. All need cross-pollination . 
In the clearings and pastures bees and other insects have crossed 
the blackberry species for the last 100 to 300 years . 
Raspberry, Blackberry, Dewberry f Rubus ) 
Robbins, W. W. 
1931. The botany of crop plants. Ed. 3, 608 pp. Philadelphia. 
p. 340: Pollination. As a rule the anthers and stigmas mature 
simultaneously. There is abundant nectar secreted by a fleshy ring 
on the margin of the receptacle, inside of the stamens. Insects 
facilitate pollination. Better yields are secured, in the case of 
some dewberries, if they are planted adjacent to another variety so 
that cross-fertilization will result. 
Blueberry and Huckleberry 
Merrill, T. A. 
1936. Pollination of the liighbush blueberry. Mich. Agr. Expt. Sta. 
Tech. Bui. 151, 34 pp. 
p. 33: Of much greater importance than self or cross-pollina- 
tion, though it receives little space in this report, is the need 
of insuring some (any) sort of pollination. Mechanical aid is 
absolutely necessary to a good set, from self as well as from cross- 
pollination. 
Bumble-bees and honey bees play a very active part in blueberry 
pollination . 
Phipps, C. R. 
1930. Blueberry and huckleberry insects. Maine Agr. Expt. Sta. Bui. 
356, pp. 107-232. 
p. 116: In conclusion, then, the investigations thus far have 
shown: (1) that various species of insects, especially honey-bees . 
bumble-bees and other bees, collect blueberry pollen; (2) that such 
insects undoubtedly exert a marked influence on blueberry pollina- 
tion since their exclusion affects yields so strikingly. 
Cherry 
Lagasse, F. S. 
1928. Proper pollination of fruit blossoms. Del. Univ. Agr. Ext. 
Bui. 15, 20 pp. 
