Embryogeny in the California Peonies with Reference to Their Taxonomic Position

Abstract

Cave, Marion S. (U. California, Berkeley), Howard J. Arnott, and Stanton A. Cook. Embryogeny in the California peonies with reference to their taxonomic position. Amer. Jour. Bot. 48(5): 397–404. Illus. 1961.—The embryogeny of Paeonia californica Nutt. ex T. and G. and P. brownii Dougl. ex Hook. is described. No cell wall is formed at the end of the first division of the zygote nucleus, but instead, a massive coenocytic proembryo is produced. This structure becomes cellular, and numerous embryo primordia form on its surface, one of which gains ascendancy over the others to form the embryo proper, consisting of root, shoot apex, epicotylar leaf primordium, and 2 cotyledons. The embryogeny of the California peonies is essentially similar to that of P. anomala, P. moutan, and P. wittmanniana described by Yakovlev and Yoffe, and does not support the contention of Murgai that in P. albiflora, P. actiflora, P. delavayi, and P. suffruticosa the coenocyte is a suspensor. It is suggested that the coenocytic embryos of gymnosperms and Paeonia represent a case of parallel evolution rather than that there is any implication of phylogenetic relationships between them.