Pollen structure and development in Nymphaeales: insights into character evolution in an ancient angiosperm lineage.

Premise Of The Study: A knowledge of pollen characters in early-diverging angiosperm lineages is essential for understanding pollen evolution and the role of pollen in angiosperm diversification. In this paper, we report and synthesize data on mature pollen and pollen ontogeny from all genera of Nymphaeales within a comparative, phylogenetic context and consider pollen evolution in this early-diverging angiosperm lineage. We describe mature pollen characters for Euryale, Barclaya, and Nymphaea ondinea, taxa for which little to no structural data exist.

Branch architecture in Ginkgo biloba: wood anatomy and long shoot-short shoot interactions.

Premise: Ginkgo, centrally placed in seed plant phylogeny, is considered important in many phylogenetic and evolutionary studies. Shoot dimorphism of Ginkgo has been long noted, but no work has yet been done to evaluate the relationships between overall branch architecture and wood ring characters, shoot growth, and environmental conditions. •

Methods: Branches, sampled from similar canopy heights, were mapped with the age of each long shoot segment determined by counting annual leaf-scar series on its short shoots.