Embryology and systematic position of Corokia A. Cunn. (Argophyllaceae, Asterales)

Embryology and systematic position of Corokia A. Cunn. (Argophyllaceae, Asterales)

Embryology of Corokia has been studied in order to utilize the data for taxonomic considerations. Anther wall consists of epidermis, endothecium, middle layer and tapetum. The ontogeny conforms to Dicotyledonous type. Pollen grains are spheroidal and three-zonocolporate. The ovules are anatropous, unitegmic, and tenuinucellate with a distinct endothelium. Embryo sac development is of Polygonum type. Development of the endosperm is of Cellular type. Both chalazal and micropylar endosperm haustoria are present. The embryogeny conforms to the Chenopodiad type. At the mature embryo sac stage, the integument consists of 1012 layers of cells. In the mature seed only the outer epidermis of the integument persists. The ripe fruit is drupaceous with stony endocarp. Based on embryological characters, considered together with relevant information on morphology, anatomy, cytology and chemotaxonomy of groups regarded related in the past, Corokia deserves to be elevated to the rank of a family, Corokiaceae. The Corokiaceae can be appropriately placed, along with Stylidiaceae, in the order Asterales.