Embryological studies inMecardonia procumbens (Miller) small

Abstract

Sporogeneses, development of gametophytes, endosperm and embryo ofMecardonia procumbens (Miller) Small have been described. The wall of the microsporangium consists of an epidermis, an endothecium, a middle layer and a glandular tapetum. The development of the anther conforms to the dicotyledonous type. The tapetal cells become binucleate and the endothecial cells acquire fibrous thickenings in later stages. Quadripartition of the microspore mother cells is simultaneous. Pollen grains are shed at two-celled stage and are tricolpate. Development of the female gametophyte is of Polygonum type. Middle part of the gametophyte is surrounded by an endothelium. Endosperm is ofab initio cellular type. Chalazal and micropylar haustoria are organised. Both the micropylar and chalazal haustoria are four-celled and this is the first report in the tribe Gratioleae. Embryo development is of Onagrad type. The cell ‘d’ functions as the hypophyseal cell.