• Govindappa D Arekal

      Articles written in Proceedings – Section B

    • Contribution to the embryology ofChaenorrhinum Minus (L.) Lange

      Govindappa D Arekal

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      The paper reports on an embryological investigation ofChaenorrhinum minus. The development of the female gametophyte is of the Polygonum type. The antipodal cells degenerate early. The endosperm isab initio cellular. The chalazal haustorium is unicellular and binucleate, although occasionally a uninucleate state occurs. No micropylar haustorium is organized. The persistent, thick-walled endothelial cells contribute to the 4–5-layered seed coat. The findings have been evaluated in the light of previous work on the tribe Antirrhineae.

    • Embryology ofVeronica serpyllifolia L.

      Govindappa D Arekal

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      The young microsporangial wall ofVeronica serpyllifolia L. is made up of four layers of cells, the innermost being the glandular tapetum. During later stages the tapetal cells become binucleate, the middle layer breaks down and the endothecial cells acquire band-like thickenings on their tangential walls.

      Quadripartition of the microspore mother cells is simultaneous. The pollen grains at the time of release are two-celled.

      Development of female gametophyte in the unitegmic, tenuinucellate, hemianatropous ovules conforms to the Polygonum type. An endothelium surrounds the middle part of the mature embryo sac.

      The endosperm isab initio cellular and is haustorial. The chalazal haustorium is unicellular, binucleate and tube-like. It comes in contact with the terminal end of the conducting strand of young seed. The micropylar haustorium, made up of two binucleate cells to begin with, becomes a 4-nucleate body after cell-fusion. The extension of this haustorium is intercellular in the initial stages but becomes intracellular in later stages and comes in contact with the conducting strand near the micropylar part of the seed.

      Development of the embryo conforms to the Crucifer type. The celld functions as the hypophysis.

      The embryological data obtained in the study have been evaluated in the light of previous work in the tribe Digitaleae.

    • Contribution to the embryology ofLindernia hyssopioides (L.) Haines

      Govindappa D Arekal S Girijamma S N R Swamy

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      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.

    • Additional notes onFarmeria indica Willis (Podostemaceae)

      Govindappa D Arekal C R Nagendran

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