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Coulter, Barnes, and Cowles, A Textbook of Botany, Vol. I. American Book Company.
Duggar, Plant Physiology. The Macmillan Company.
Ganong, The Teaching Botanist. The Macmillan Company.
Goebel, Organography of Plants, Part V. Clarendon Press.
Goodale, Physiological Botany. American Book Company.
Gray, Structural Botany, Chap. V. American Book Company.
Kerner-Oliver, Natural History of Plants. Henry Holt and Company.
Strasburger, Noll, Schenck, and Karston, A Textbook of Botany. The Macmillan Company.
Ward, The Oak. D. Appleton and Company.