Plant evolution dances to a different beat

Abstract

Land plants have origination rates comparable to those of some animal groups, but the driving forces for evolution of plants differ. Floral transformations have been due to gradual replacement and piecemeal, not mass extinction. Plant “geoevents”; have not been synchronous with epochal animal originations/ extinctions and hence may not be attributable to the same causes. Initiation of new plant forms probably results primarily from intrinsic genetic factors. Plant taxa are much less subject to extrinsic factors than are comparable animal groups. Plants evolve related forms adapted to very different environments; hybridity and polyploidy produce variants with different qualities in some organs. Mosaic evolution is thus characteristic of plants. Heterochrony has probably permitted rapid shifts in timing of ontogeny to produce new life‐forms. Vegetative reproduction and persistence, indeterminate growth, potential long dormancy of propagules, comparative freedom from demands of population size, and comparati...