ANATOMY AND DEVELOPMENT OF THE FLOWER AND FRUIT OF PERESKIA PITITACHE

Boke, Norman H. (U. Oklahoma, Norman.) Anatomy and development of the flower and fruit of Pereskia pititache. Amer. Jour. Bot. 50 (8): 843–858. Illus. 1963.—Flowers of P. pititache are about 6 cm in diameter and perigynous. The receptacle bears numerous broad bracts; the inner perianth segments are orange and deeply cleft; the numerous stamens develop centrifugally. The fundamentally superior gynoecium is broad and flat and consists of 10–18 connate carpels, the fertile portions of which are involute and adnate to the conical floral axis. The 8–16 ovules in each of the pocket-like locules are borne in 2 rows along the zone of adnation; placentation is axile. The short style and the style branches are lined with stigmatic tissue, which extends downward among the ovules. There is no definite stigma. The tip of the floral axis retains its meristematic characteristics beyond anthesis. In early fruit development, the rim of the floral cup grows in height, while the residual floral axis becomes a conspicuous peg-like columella. Concomitantly, the formation of numerous mucilage cells and cavities causes the ovary partitions and parts of the ovary roof to disintegrate. As a result, the seeds are contained in a single, moat-like cavity, which appears inferior. Late fruit development is characterized by the differentiation of numerous fiber sclereids in association with the extensive and complex vascular system.