Evolutionary trends in the reproductive biology of angiosperms

Abstract

Which embryologic characters are primitive, and which are advanced, has long been a controversial issue? The comparative embryology of angiosperms and gymnosperms does not provide any useful clue. Single embryological characters are not as useful for phylogenetic and evolutionary considerations as are a group of characters. Moreover, some of the characters may be merely adaptive without any evolutionary significance. The numerous variations cause further complication.

This article is devoted to (a) distribution and phylogeny of anther tapetum, (b) affinities of megagametophyte, (c) can the angiosperm embryo sac be derived from the archegonium in gymnosperms?, (d) primitive and advanced embryological features, and (e) embryological features in Magnoliiflorae s.1. and certain Liliiflorae.