Studies on the Monimiaceae. III. Gametophyte development of Laurelia novae-zelandiae A. Cunn. (subfamily Atherospermoideae)

Abstract

Floral ontogeny and gametophyte development of the New Zealand endemic species Laurelia novae-zelandiae is described. The microsporangium has three to five wall layers inside the epidermis, including a typically thickened endothecium and a tapetum of the secretory type in which the cells become binucleate during the first meiotic division of pollen mother cells. Cytokinesis of pollen mother cells is of an unusual type in which centrifugal cell plates do not develop until the end of meiosis 11. The generative cell of the pollen grain is cut off against what represents a radial wall of the grain with reference to the tetrad stage. Pollen is two- or three-celled when shed.

Ovules are bitegmic, crassinucellate, and anatropous with a Polygonum type of embryo sac development.