- 41 - 
of bees were known to exist in this area, though possibly there 
were some wild swarms present. 
Sunflower 
Rudnev, V. Z. 
194-1. [The effect of pollination by bees on yield of sunflower seeds.] 
Soc. Zern. Hoz. No. 2. 134-4.0. [Abstract in Imp. Pur. 
Pastures and Forage Crops, Herbage Abs . 14-:55-56, 194-4.] 
p. 55: Field tests with % sunflower plants, which were either 
completely or partially covered with gauze to prevent pollination 
by the bees, indicated that percentage of settings was 77.7 to 
85. 9 in the insect-pollinated and 25.0 to 25.7 in the self-polli- 
nated flowers. Trials in field conditions (when a number of bee- 
hives was placed at varying distances from several observation 
plots 100 ra each in a large sunflower plantation) showed that, 
with the increase from 500 to 1250 m. of the distance of a beehive 
from the plantation, the number of bees visiting each plot daily 
fell from 100 to 61, the weight of ripe seeds dropped from 6,000 
to 3,700 grm., and the weight of empty seeds rose from 110 to 200 
grm. 
Sweetclover 
Posters, A. J., and Hollowell, E. A. 
1937. Clover improvement. U. S. Dept. Agr. Yearbook 1937: 1190-1214. 
p. 1207: Pollination o f sweetclover under natura l con ditions 
is effected principally by honeybees, except insofar as the 
species, varieties, or individuals are spontaneously self-fertilized. 
United States Department of Agriculture. 
194-2. A much larger harvest of hay crop seeds needed in 1942. U. S. 
Dept. Agr. Food for Freedom Program, Background Information Series, 
No. 7, 5 pp. 
p. 3s ... lack of sufficient pollination lowers seed yields. 
Honeybees are the most valuable pol l inators . A minimum of one 
hive of honeybees per acre located close to a blossoming field 
of sweet clover will increase the quantity of seed set. 
Trefoil 
McKee, R., and Schoth, H. A. 
194-1. Birdsfoot trefoil and big trefoil. U. S. Dept. Agr. Cir. 625, 
13 pp. 
p. 5: The general conclusion of investigators who have studieu 
seed setting in Lotus species is that both birdsfoot trefoil and 
big trefoil are practically self-sterile. Silow ... who has more 
