(42) 



and stone-like as any coral, and build up reefs in the tropi- 

 cal oceans much as the corals do. 



The next great type of plant life is the fungi (cases 17 

 to 36). These, like the plants of the preceding group, 

 vary greatly in size and complexity of structure; but, 

 unlike them, they are devoid of chlorophyl, the character- 

 istic green matter which enables other plants to build up 

 complex food for their nourishment, and consequently 

 they are wholly different in their mode of life. Some are 

 parasitic, deriving their nourishment from living plants 

 and causing enormous damage to crops; others are sap- 

 rophytic, deriving it from the remains of dead organisms; 

 while others are symbiotic, living in such relationship with 

 chlorophyl-bearing (green) plants that they mutually 

 nourish one another, as in the case of mycorhizas. There 

 are five generally recognized series here: First we have the 

 stalked-spored fungi (cases 17 to 28). This series falls into 

 two groups, the one typified by the "rusts" and "smuts" 

 which are commonly parasitic on the leaves and fruits of 

 other plants; the other the great saprophytic group, well 

 known through the mushrooms, bracket-fungi, stink- 

 horns, and puff-balls. Second in the series is the group 

 known as the imperfect fungi (case 29). In this group the 

 spores are borne directly on the threads or "hyphae" 

 which constitute the vegetative portion of the organism. 

 They are often parasitic on the leaves and on the bark 

 of both wild and cultivated plants. Third in this series 

 are the spore-sac fungi (cases 30 and 31). In these plants 

 the spores are borne in delicate membranous sacs, called 

 asci, which in the more complex forms are collected into 

 bodies of various shapes. The plants vary greatly in 

 size and structure and may be either parasitic or sapro- 

 phytic. To this group belong the yeasts and mildews. 

 To this group also belongs the chestnut-blight fungus. 

 This fungus disease which has been imported into this 

 country has caused the death of all of the American 

 chestnut trees in the immediate vicinity of New York 



