The embryology of Kunzea capitata Reichb

Abstract

The anther is tetrasporangiate and the development of its wall is of the Basic type. Ubisch granules are formed on the surface of the tapetum at the signet-ring stage of the pollen grains. The anther dehisces by longitudinal slits, and pollen grains are shed at the two-celled stage.

The female archesporium is subepidermal and cuts off the primary parietal cell. A six-layered parietal tissue is formed below the nucellar epidermis by the time megasporogenesis is completed. The flowers are protandrous, and in any given bud meiosis in megaspore mother cells follows that in microspore mother cells. Embryo sac development is of the Polygonum type and the antipodal cells are ephemeral.

Cell formation in the nuclear endosperm commences at the micropylar end and proceeds towards the chalaza. Embryogeny corresponds to the Onagrad type and no evidence of polyembryony was found.

Both the integuments take part in the formation of the seed coat, in which the cells of the outer layer of the outer integument are conspicuously elongated.

A comparison is made with the embryological findings in other myrtaceous plants.