Pollen Grains: Their Structure, Identification and Significance in Science and Medicine

Abstract

This is an exhaustive study of the history and basic principles of pollen morphology, with a key and descriptive classification of the pollen grains of 450 species of the wind pollinated plants of North America. Accompanying the text, but not in a convenient position for comparison with the descriptions, are beautiful enlarged drawings of the pollen grains of about a third of the species discussed. Considerable space is devoted to the genesis and phylogenic significance of pollen grain characters. Even the eternal question of heredity versus environment is not overlooked, as evidenced by "Inasmuch as the numerical type of symmetry of the pattern is determined by the position and number of the germinal apertures, it may be stated that the number and arrangement of the elements in the symmetry patterns of pollen grains are haptotypic characters, that is to say, are the result of their cellular interrelations and directly due