Embryology of Takhtajania (Winteraceae) and a summary statement of embryological features for the family

We present the first report on the embryology of Takhtajania. By adding its data to those already known from other Winteraceae (Drimys, Pseudowintera, Tasmannia, and Zygogynum s.l.), we summarize embryological features of the family to evaluate the proposed basal position of Takthtajania in the fami ly and a possible sister-group relationship between Winteraceae and Canella ceae, which were recently suggested by molecular evidence. Comparisons with in and between the families showed that Takhtajania agrees well with other Winteraceae embryologically, having no distinct features to support its bas al position in the family. Although Winteraceae and Canellaceae share a num ber of basic embryological features, including an exotestal seed coat,Winte raceae are clearly distinct by virtue of the following features: the outerm ost one of the middle layers and even part of the connective tissue in the anther developing fibrous thickenings at anthesis; ovules anatropous (not c ampylotropous as in Canellaceae); the micropyle formed by the inner integum ent alone (rather than by two integuments as in Canellaceae); an exostome f ormed after fertilization; a persistent micropylar part of the tegmen compo sed of variously enlarged, thick-walled cells; and the exotesta palisadal. Winteraceae are thus a well-defined group embryologically and, despite thei r modern widespread distribution, genera show little diversification in emb ryological characters.