Embryology of Drimys winteri

Abstract

Drimys is one of six genera of the vesselless family, Winteraceae.The genus includes nearly 40 species of which 36 occur in the Old World and the rest are found in the Americas.The family is of interest because of the presence of numerous primitive characters such as the undifferentiated stamens in some members; a complete series from an open conduplicate to a closed carpel which may be sessile or stipitate; stigmatic crest; laminar placentation, and primitive xylem without vessels.Bailey (1944), Bailey and Nast (1943a, b; 1944a, b;1945), and Xast (1944) have dealt extensively with the morphology and vegetative anatomy of various members of the Winteraceae.However, literature on its embryology is rather meager.Maheshwari (1950), while discussing the relationships of angiosperms with other groups, has remarked "Regarding the relationship of the angiosperms with other groups, we are at present entirely in the dark.It is possible that a study of morphology and embryology of Degeneriaceae, Winteraceae, Trochodendraceae etc., may throw some light on the problem."So a study of the embryology of the Winteraceae was taken up (see Bhandari, 1963) and the present investii of that project.PREVIOUS WORK Strasburger (1905) made some preliminary observations on the ovule and embryo sac of Drimys winteri var.winteri and reported normal embryo sac and nuclear endosperm.Bhagawathi Kutti Amma (1938) studied the details of microsporogenesis in Drimys and recorded amoeboid anther tapetum.On the other hand, Swamy (1952) observed secretory tapetum, normal embryo sac, and cellular endosperm in Zygoj^ynum baillonii.In P seudowintera colorata (Bhandari, 1963) the tapetum is amoeboid but in P. axillaris (Sampson, 1963) it is secretory.In both species the embryo sac is of the Polygonum type, and endosperm is cellular.Post-fertilization stages in the ovules and pericarp have been followed only in P. colorata (Bhandari, 1963). MATERIAL AND METHODSThe buds, flowers, and fruits of Drimys winteri were obtained by the late Professor P. Maheshwari through the courtesy of Dr. V. Garcia of Argentina.The collections were fixed on the spot in FAA and later stored in 70 percent ethanol.The material was passed through alcohol-