Staminate Flower of Echinocystis lobata

Abstract

The order of appearance of organs in floral development is sepal, petal, stamen. At the time of anthe-sis the corolla is sympetalous, but in ontogeny the petals develop with separate individualities, and their apparent fusion later is more incidental than fundamental. The flower is therefore considered to be fundamentally polypetalous. The bisporangiate stamen is a normal and complete organ. The tetrasporangiate stamen is a double one, developing from 2 separate primordia. These, however, are in such close proximity that the receptacle tissue between them becomes involved in the upward growth, and the 2 organs develop into 1 large staminate mass. Although the stamens are but 3 in number, 1 single and 1 double, they are, believed, by reason of the relations of the vascular supplies to similarly situated staminodia in the pistil-} late flower, to be members of 2 stamen cycles. The single stamen rises opposite a petal, 1 stamen of the combined 2 also rises opposite a petal, and the 3rd rises opposite a sepal. The nature of the corolla casts further doubt on the logic of retaining the Cucurbita-ceae in the Sympetalae line.