Plant embryology : embryogeny of the spermatophyta / by Donald AlexanderJohansen . Johansen, Donald Alexander, 1901- Plant embryology. QK665 .J6 581.3 JOP Includes bibliographical references and index. Waltham, Mass : Chronica Botanica , 1950. 1950. 1950 Text xvi, 305 p. : eng A New series of plant science books, v. 24