Plant variation and classification / by C. Ritchie Bell. Drawings by Susan Carlton Smith. Bell, C. Ritchie. Plants Classification. Plants Variation. QK95 .B38 581.15 BEP Includes Bibliography p. 121-125. Belmont, Calif. : Wadsworth Pub. Co. , c1967. c1967. 1969 Text vi, 135 p. : eng Fundamentals of botany series