CHAPTER VI

BIONOMICS

A. GROWTH AND DURATION OF LICHENS 252

B. SEASON OF FRUIT FORMATION 255

C. DISPERSAL AND INCREASE 256 _a._ Dispersal of crustaceous lichens _b._ Dispersal of foliose lichens _c._ Dispersal of fruticose lichens

D. ERRATIC LICHENS 258

E. PARASITISM 260 _a._ General statement _b._ Antagonistic symbiosis _c._ Parasymbiosis _d._ Parasymbiosis of fungi _e._ Fungi parasitic on lichens _f._ Mycetozoa parasitic on lichens

F. DISEASES OF LICHENS 268 _a._ Caused by parasitism _b._ Caused by crowding _c._ Caused by adverse conditions

G. HARMFUL EFFECT OF LICHENS 269

H. GALL-FORMATION 270