Contents. xi 



LECTURE XXV. 



RANUNCULUS BULBOSUS. 



Gymnosperms and Angiosperms The buttercup Structure of the stem and 

 its conducting tracts Function of the bundle-sheath Arrangement of 

 tissues in the leaves and roots Cohesion-theory of the ascent of water 

 in plants Meaning of the subdivision of the water channels and of the 

 pits Root-pressure pages 215-229 



LECTURE XXVI. 



RANUNCULUS BULBOSUS. 



Flowers of the buttercup Stamens and carpels Origin of the pollen-grains 

 and embryo-sacs Liberation of pollen-grains Insect-pollination 

 Growth of male gametophyte Development of female gametophyte 

 Fertilisation Embryo and endosperm Seed Comparison with the Pine 



pages 230-238 



LECTURE XXVII. 



SdLLA NUTANS. 



Dicotyledons and Monocotyledons The wild hyacinth Arrangement of 

 tissues in roots, stems and leaves Stamens Fused carpels Gameto- 

 phytes Embryology pages 239-249 



LECTURE XXVIII. 

 NUCLEAR DIVISION. 



All cells of adult directly descended from oosperm Parts of a nucleus 

 Somatic mitosis Chromomeres of nuclei in adult derived by fission 

 from those of oosperm Chromatin : the germ-plasm Reducing mitosis 

 Want of equivalence in the chromomeres of resulting nuclei 



pages 250-259 



LECTURE XXIX. 

 HEREDITY. 



Inherited and acquired characters Mendel's observations Determinants 

 Dominance Proportions of progeny showing the dominant and the 

 recessive character Segregation of determinants Interaction of 

 characters pages 260-269 



LECTURE XXX. 

 EVOLUTION THEORY OF DESCENT. 



Origin of species by evolution Evidence from morphology, from distribu- 

 tion and from palaeontology Natural selection Lamarkism Segrega- 

 tion and new combinations of determinants . . . pages 270-278' 



INDEX pages 279-291 



