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A B S T R A C T A comparative study of carpellary structure in the spiraeoid subtribes Quillajeae and Sorbarieae has shown that morphological inter-relationships are similar to those of other Rosaceae. When the suture is closed the carpels tend to be coherent and the ovular and wing bundles tend to be fused. These relationships are statistically significant in the Spiraeo deae as a whole. The construction of the gynoecium in Lindleya and in most species of Vauquelinia resembles that of a pomoid. Other features of a pomoid-spiraeoid affinity have been discussed. sub-tribes of the Spiraeoideae: Holodisceae, Neillieae, Spiraeeae, and Ulmarieae. The present study deals with the two remaining sub-tribes of this group: Quillajeae and Sorbarieae. Both Maximowicz (1879) and Jue (1918) regarded the Quillajeae as the most primitive sub-tribe of the Spiraeoideae. On the basis of the vascular structure of the pedicels and carpels, Bonne (1928) agreed with this view and declared that the other groups in the Rosaceae could be considered to diverge from the

A B S T R A C T 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. THE FEATURES of carpels in presumably primi