. Day length and crop yields. Plants; Crop yields; Plant photoperiodism. Light for an hour in the middle of the dark period delays the blooming of chrysan- Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Parker, M. W. (Marion Wesley), 1907-; Borthwick, H. A. (Harry Alfred), 1898-. Washington, D. C. : U. S. Dept. of Agriculture

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Keywords: ., bookcentury1900, bookpublisherwashingtondcusd, booksubjectplants