Contribution to the embryology ofLindernia hyssopioides (L.) Haines

Abstract

The results of an embryological investigation ofLindernia hyssopioides (L.) Haines [=Ilysanthes hyssopioides] (L.) Benth.] have been presented. The young anther wall consists of three layers of cells in addition to the glandular tapetum. The tapetal cells become binucleate and the nuclei fuse together. The endothecium acquires fibrous thickenings in later stages and the middle layer disorganizes. Quadripartition of microspore mother cells is simultaneous. The pollen grains at shedding are two-celled and tricolpate. The ovules on the massive axile placenta of the superior bicarpellary syncarpous ovary are anatropous, unitegmic and tenuinucellate. The development of the embryo-sac conforms to the Polygonum type. The two synergids are posteriorly vacuolate and have tapering anterior ends. The antipodal cells are ephemeral. The endosperm isab initio cellular. The division of the primary micropylar endosperm chamber is vertical and not transverse. The chalazal haustorium consists of two uninucleate cells. Occasionally it becomes 3-celled. The micropylar haustorium is made up of 4 uninucleate cells. The haustorial cells neither develop lateral extensions nor fuse together during seed development. The development of the embryo is of the Crucifer type. The daughter cell ofd functions as the hypophysis. The seeds are albuminous. The remains of the endothelium and the outer epidermis of the integument constitute the seedcoat. The results obtained have been evaluated in the light of earlier work in the tribe Gratiolae.