These data were read from a figure in Bieberdorf, G.A. & E. Hale. The nectar flow at Stillwater during 1938 as indicated by a scale colony of bees. Proceedings of the Oklahoma Academy of Sciences for 1938. pp 78-80.
Note: The figure is on p 78, whereas the article begins on p 79.
The paper describes the nectar flow in 1938 as beginning later than usual, with higher gains in Jun/Jul than previous years.
The nectar sources are listed in order of appearance - locust in the spring, followed by false indigo, hoar-hound, yellow sweet clover, vetch, alfalfa, white sweet clover, horsemint, chinaberry and cotton on Jul 25.
In 1938 most nectar in Jun and the first 2 wks in Jul was from sweet clover and alfalfa, while alfalfa and cotton dominated in the last 2 wks of Jul thru Aug. Typically there is a dearth from mid Jul to Aug, with a fall flow (the second of the year) beginning in mid-Sep.
If anyone knows where the OSU apiary was located in 1938, please let us know.