Abstract
The carpels of the Holodisceae, Neillieae, Spiraeeae, and Ulmarieae are usually separate from one another; most have open sutures, and their ovules tend to be monotegmic. The ovules are epitropic in Holodisceae, Spiraeeae, and Ulmarieae; they may be pleurotropic, apotropic, or epitropic in the Neillieae. In many species the carpels are partly fused with the floral cup. Only in Luetkea and some species of Spiraea and Stephanandra are the ovular and wing bundles separate at the base of the locule; in the other species ventral bundles persist above that level before dividing. In species with open sutures, the ovules are mostly bitegmic, and the ovular bundles tend to be separate from the wing bundles at the insertion level. An evolutionary trend towards fusion of the two ventral bundles with each other and with the dorsal bundle is shown. In Filipendula the dorsal bundle may be absent. A possible relationship between the Spiraeoideae and the Pomoideae is discussed.
Funding Information
  • National Science Foundation (G 16142)