Variation in Trifolium pratense presents many interesting problems, some of which have been under consideration during the past two seasons by the contributors to this paper. General relationships between number of flowers in the head, and number of seeds produced, the influence of soils, and seasons, comparative dimensions of the flowers, and of pollen grains, were the particular features studied.
Proceedings of the Iowa Academy of Science
©1911 Iowa Academy of Science, Inc.
Pammel, Edna C. and Clark, Clarissa
"Studies in Variation of Red Clover,"
Proceedings of the Iowa Academy of Science, 18(1), 47-53.
Available at: https://scholarworks.uni.edu/pias/vol18/iss1/11