APOMIXIS AND POLYEMBRYONY IN HIEROCHLOË ODORATA

Abstract

Norstog, Knut. (Wittenberg U., Springfield, Ohio.) Apomixis and polyembryony in Hierochloe odorata. Amer. Jour. Bot. 50(8): 815–821. Illus. 1963.—Hierochloë odorata from Michigan, having 2n = 56 chromosomes, was found to reproduce by pseudogamous fertilization of diploid aposporous embryo sacs. Diploid embryos, 2n= 56, and 5n = 140 ± endosperm occurred together. Megasporogenesis was incomplete, and aposporous embryo sac initials developed directly into 8‐nucleate Polygonum type embryo sacs. Microsporogenesis was irregular with univalent, bivalent and multivalent chromosomes in meiosis‐I. Dyads and microspores varied between n = 24 and n = 32, and less than 50% of the pollen grains stained with acetocarmine. Two other races of H. odorata are known to occur in North America. They are an apparently infertile type in Canada with 2n = 28, and a perfectly fertile race from coastal Connecticut also with 2n = 28. It is suggested that the H. odorata with 2n = 56 is a derivative of the sterile Canadian race.