Embryology of Phryma leptostachya L. (Verbenaceae) with considerations of its systematic status and affinities

Abstract

AbstractSome embryological aspects – structure and development of the microsporangium, microporogenesis and male gametophytes; embryogeny and some features of seed‐coat of Phryma leptostacha L. have been studied. The microsporangial wall develops confirming to the Dicot type of Davis (1966). The anther tapetum is secretory and displays dual origin. Endothecial cells exhibit fibrous thickenings. The tricolpate pollen grains are shed at 3‐celled stage. The embryogeny follows the Hyoscamus variation of the Solanad type (Johansen 1950) or the Period‐I, Series C, Megarchetype IV of Soueges (1948). The mature embryo is dicotyledonous. Only a papery layer of endosperm encompasses the embryo. In the light of the present study with the other relevant informations from diverse sources the taxonomic status of the taxon Phryma leptostachya L. is examined. It is suggested, that this genus is undoubtedly related to some verbenaceous taxa and so merits to be retained in a separate tribe (Phrymeae) of its own nearer but not within the sub‐family Verbenioideae, a view expressed by Thorne (1976, 1983, 1992) and Takhtajan (1980, 1987).