xiv CONTENTS, 



PAGE 



Lecture XL. — The Anisotropy of the Organs of Plants "9° 



Definition of Anistropy.— Anistropy a cause of the Configuration of Plants.— Radial 

 Organs are Orthotropic, Dorsi-ventral ones Plagiotropic. — Radial Organs react 

 alike on all sides, Dorsiventral ones differently.— RoUed-up Plagiotropic Organs are 

 Orthotropip.- Plagiotropic Lateral Roots.— Shoots of Marchantia.— Plagiotropic 

 Organs consist of Orthotropic parts.— Plagiotropism of the \vy.—Trofceolum, 

 Gourd, etc.— Torsion in Plagiotropic Lateral Shoots.— Hydrotropism.— Positive 

 and Negative Hydrotropism. 



PART VI. — Beproduction. 



Lecture XLL— The Organs of Reproduction— General Considerations— Algas ; 



Fungi ; Archegoniata 721 



Vegetative Multiplication. — Alternation of Generations. — Ascomycetes. — Con- 

 jugatse. — Gametes. — Zygotes. — Oospheres and Antherozoids (Spermatozoa, Zoo- 

 sperms). — Reproduction of Vaucheria. — Alternation of Generations in the Moss. — 

 Archegonia and Antheridia of the Moss. — Embryo of the Moss. — Reproduction of 

 the Vascular Cryptogams. — Sporangia and Spores of Equisetum. — Prothallium 

 oi Equisetum. — Embryology of the Fern. 



Lecture XLIL— The Organs of Reproduction, continued. — Heterosporous Vas- 

 cular Cryptogams ; Gymnosperms ; Angiosperms . . . . ' . . 745 



Reproductive apparatus of Marsilia. — Embryology of Marsilia. — Formation of 

 Embryo inside the Macrospore. — Pollen-grains, Pollen-tube, Embryo-sac. — Naked- 

 seeded Plants. — Nature of the Ovule and of the Seed. — Fertilisation by means of a 

 Pollen-tube. — Development of the Seed in Gymnosperms. — Angiosperms or trae 

 Flowering Plants. — Flowers of Angiosperms. — Fertilisation of Angiosperms. — Stigma 

 and Pollen-tube. — Seeds vrith and without Endosperm. — Embryology of Angiosperms. 



Lecture XLIIL — The Action of Sexual Cells upon one another (Continuity of 



Embryonic Substance) 767 



The Essentials of Fertilisation. — Continuity of Embryonic Substance. — Mutual 

 Action at a distance of Sexual Cells. — Strasburger on the Fertilisation of Ferns. — 

 Juranyi on the Fertilisation of (Edogonium. — Behaviour of Conjugating Gametes. — 

 Action at a distance in Peronosporese. — Pollen-tubes. 



Lecture XLIV.— Transmission and Blending of the Paternal and Maternal Pro- 

 perties by Fertilisation (Hybrids) 779 



Only nearly allied Forms hybridise. — Mingling of Parental Characters. — SexuaUty 

 of Hybrids.— Millardet on the Hybrids of the Vine.— Resistance of Hybrid Vines 

 to the attacks of Fungi and Phylloxera. 



787 



Lecture XLV.— Influence of the Origin of the Sexual Cells of the same species on 

 the Result of Fertilisation 



Dichogamy, HeterostyUsm, Herkogamy.— Pollination by the aid of Insects.— ^m- 

 tolochia Clematitis. — Pollination in Aj/otW— Pollination in Viola and EpipacHs. 



Lecture XLVL— The Object of Fertilisation. Apogamy 798 



Importance of Sexual Organs and Sexual Propagation. — Apogamy. Vegetative 



multiplication of Apogamous Plants. 



INDEX 



803 



