Flower Development and Gametogenesis in Oenothera laciniata Hill

Calyx, carpels, stamens, and corolla arise in acropetal succession. The wall of the anther has four layers of cells. The tapetum is binucleate and is of glandular type. Tricolpate pollen grains are triangular in outline and are binucleate at the time of shedding. The cells of the endothecium have spiral thickenings. Development of the ovule is described. The synergids have filiform apparatus with prominent hooks. Pollen tube enters porogamously and destroys one of the synergids during its entry. A hypostase is organized at the chalazal end of the ovule. The present observations are discussed in relation to the previous literature