CONTENTS. 



PAGE 

 141 



Lecture IX. — Systems of Tissue, continued. Fundamental Tissue. Rudimentary 

 Differentiations of Tissue ........... 



Fundamental Tissue. — Hypoderm. — Sheaths. — Sclerenchyma. — Assimilatory Paren- 

 chyma. — Tissue-systems of Mosses. — Differentiations of Tissues in Algse. — Differ- 

 entiations of Tissues in Fungi. 



Lecture X. — Secondary Growth in Thickness of Shoot- Axes and Roots . . 155 



Correlation between Growth in Thickness and extent of Foliage. — Cambium-ring. — 

 Products of Cambium. — Wood. — Heart-wood and Alburnum. — Cork, Periderm. — 

 Bark. — Lenticels. — Secondary Growth in Thickness of Monocotyledons. 



Lecture XL — Laticiferous Vessels and Receptacles for Secretions . . . 171 



Latex-tubes. — Variety of Secretions. — Calcium Oxalate.— Calcium Carbonate. — 

 Secretion-vesicles. — Resin- and Gum-canals. — Internal Glands. — Epidermal Glands. 



PART II. — The External Conditions of Vegetable-life, and the 

 Properties of Plants. 



Lecture XI L— The General External Conditions of Plant-Life .... 189 

 Organic Structure and External Influences. — Cardinal Points of Temperature 

 suitable for Vegetation.- — Representation of the Dependence by Curves. — General 

 Law of Dependence. — Dependence on Light. — Daily Periodicity. — Influence of 

 Gravitation, Light, Electricity. — Dependence on Habitat. — Dependence on Animals. 



Lecture XI 1 1. — The Molecular Structure of Plants and its Physiological Im- 

 portance 205 



Molecules, Molecular Complexes. — Swelling. — Diosmosis. — Turgescence. — Artificial 

 Cells. — Tissue-tensions. — Rigidity due to Tissue- tensions. — Elasticity, &c. due to 

 Lignified Sclerenchyma. 



PART III.— Nutrition. 



Lecture XIV. — The Ascent of Water in Transpiring Land-Plants . . .225 



Importance of the Water-current in Nutrition. — Transpiration from Leaves. — 

 Ascending Current in the Wood. — Sclerenchyma conducts water. — Distribution of 

 the Water-current in the Leaves. — Rapidity of the Upward Flow. — Filtration 

 through Wood. — Condemnation of the Capillarity Theory. — Calculation of the 

 Cubic Contents of the Wood-cavities. — Specific Properties of Wood. — Suction in 

 Cut Branches. 



Lecture XV. — Conditions of Transpiration — Absorption of Water and Nutritive 



Matters by the Roots of Land-Plants 246 



Regulation of Transpiration. — Mechanics of Stomata. — Stomata as the Regulators of 

 Transpiration. — Transport of Nutritive Salts in Wood. — Absorption of Water and 

 Salts by Leaves. — Water contained in the Soil. — Absorption of Water by Root- 

 hairs. — Absorption of Substances held in the Soil. — Attachment of Root-hairs to 

 Particles of Soil. — Corrosion of Minerals by Roots. 



Lecture XVI.— Excretion of Water in the Liquid State 266 



Mobility under Pressure of the Water in Wood. — Water-currents in the Wood due 

 to Changes of Temperature. — Weeping of Root-stock. — Periodic variations in the 

 Excretion of Water. — Mechanics of the Weeping of Root-stocks. — Relation of Root- 

 pressure to Transpiration. — Excretion of Drops from Leaves. — Excretion of Drops 

 by Non-cellular Plants. 



