CHAPTER V. Physiology

PHYSIOLOGY

I. CELLS AND CELL PRODUCTS

A. CELL-MEMBRANES 209 a. Chitin b. Lichenin and allied carbohydrates c. Cellulose

B. CONTENTS AND PRODUCTS OF THE FUNGAL CELLS 213 a. Cell-substances b. Calcium Oxalate c. Importance of calcium oxalate

C. OIL-CELLS 215 a. Oil-cells of endolithic lichens b. Oil-cells of epilithic lichens c. Significance of oil-formation

D. LICHEN-ACIDS 221 a. Historical b. Occurrence and examination of acids c. Character of acids d. Causes of variation in quantity and quality e. Distribution of acids

E. CHEMICAL GROUPING OF ACIDS 225 I. ACIDS OF THE FAT SERIES II. ACIDS OF THE BENZOLE SERIES SUBSERIES I. ORCINE DERIVATIVES SUBSERIES II. ANTHRACENE DERIVATIVES

F. CHEMICAL REAGENTS AS TESTS FOR LICHENS 228

G. CHEMICAL REACTIONS IN NATURE 229

II. GENERAL NUTRITION

A. ABSORPTION OF WATER 229 a. Gelatinous lichens b. Crustaceous lichens c. Foliose lichens d. Fruticose lichens

B. STORAGE OF WATER 232

C. SUPPLY OF INORGANIC FOOD 232 a. In foliose and fruticose lichens b. In crustaceous lichens

D. SUPPLY OF ORGANIC FOOD 235 a. From the substratum b. From other lichens c. From other vegetation

III. ASSIMILATION AND RESPIRATION

A. INFLUENCE OF TEMPERATURE 238 a. High temperature b. Low temperature

B. INFLUENCE OF MOISTURE 239 a. On vital functions b. On general development

IV. ILLUMINATION OF LICHENS

A. EFFECT OF LIGHT ON THE THALLUS 240 a. Sun lichens b. Colour-changes due to light c. Shade lichens d. Varying shade conditions

B. EFFECT OF LIGHT ON REPRODUCTIVE ORGANS 244 a. Position and orientation of fruits with regard to light b. Influence of light on colour of fruits

V. COLOUR OF LICHENS

A. ORIGIN OF LICHEN-COLOURING 245 a. Colour given by the algal constituent b. Colour due to lichen-acids c. Colour due to amorphous substances d. Enumeration of amorphous pigments e. Colour due to infiltration