XXX 



CONTENTS. 



PAGE 



b. Spermogones 71 



Sterigmata 72 



Spermatia 73 



c. Pycnides 75 



Sterigmata 75 



Stylospores 75 



CHAPTER III. 



Economical Applications oe Lichens . . 77 



1. Use as soil-producers 78 



2. Use as food to man and the lower animals .... 80 



Chemistry of nutrient principles 81 



3. Applications in medicine . . 83 



Chemistry of medicinal principles 84 



4. Applications in the arts 84 



a. Dyeing 84 



Chemistry of Colouring Matters . . . . . 84, 91 



b. Perfumery, Brewing, Tanning, etc .92 



CHAPTER IV. 



Geographical Distribution oe Lichens 95 



1. Longitudinal range . . 96 



2. Altitudinal range 100 



3. JIabitat, in relation to 



a. t Physical character . .. . 101 



