x Contents. 



LECTURE XIX. 



ASPIDIUM FlLIX-MAS. 



The " male fern " Formation of leaves Arrangement of the conducting 

 tracts in the fundamental tissue of the stem Branches supplying roots 

 and leaves Structure of the conducting tracts Structure of roots and 

 leaves Disposition and protection of photosynthetic cells Stomata 

 Path of water from roots to leaves Transpiration current Rigidity of 

 land-plants . . pages 146-160 



LECTURE XX. 



ASPIDIUM FILIX-MAS. 



Life-history of Aspidium Sporophylls Sori Sporangia Spores Mechan- 

 ism for disseminating spores Germination of spores Gametophyte 

 Antheridia and archegonia Fertilisation aquatic Embryo growing 

 from oosperm becomes sporophyte Amphibious life-history Arche- 

 goniates Homologues pages 161-169 



LECTURE XXI. 



SELAGINELLA MARTENSH. 



Synthetic forms Stems, leaves, rhizophores and roots of Selaginella Cones 

 of sporophylls Microspores and megaspores Heterospory Male and 

 female gametophyte Diminutive dependent gametophytes Fertilisation 

 Embryo enclosed in female gametophyte still partly enclosed in spore- 

 coat pages 170-178 



LECTURE XXII. 



PlNUS SlLVESTRIS. 



Pine tree Arrangement of scales and dwarf shoots on its branches Protec- 

 tive, photosynthetic and conducting tissues of the leaves Connection 

 of leaves with stem Structure of stem Its growing tip Growth of 

 stem in thickness Root Direct connection between absorbing ends of 

 roots with transpiring leaves pages 179-191 



LECTURE XXIII. 



PlNUS SlLVESTRIS* 



Development of a tracheid Bordered pits Comparison of transverse, radial 

 and tangential sections in the wood Outer tissues of the stem Possible 

 functions Pollen-cones Stamens, sporophylls Pollen-sacs, sporangia 

 Pollen-grains, spores pages 192-203 



LECTURE XXIV. 



PlNUS SlLVESTRIS. 



Seed-cones Carpels, sporophylls Ovules, megasporangia Embryo-sac, 

 megaspore Pollination Growth of the male and female gametophyte 

 Sperms and ova Embryo Seed Comparison of the life-history of 

 the Pine with that of the Archegoniates .... /a/^s 204-214 



