FUNGI CONTINUED: CLASSIFICATION. 217 



3. SUBCLASS EUASCOMYCETES. 



Asci associated in surfaces forming a hymenium, or in groups or inter- 

 mingled in the elements of a fruit body. Fruit body usually present. 



The following four or five orders comprise the Discomycetes, according 

 to the usual classification. 



444. Order Protodiscales (Protodiscinese). The asci are exposed andj 

 form large and indefinite groups, but there is no definite fruit body. Ex- 

 amples: leaf curl of peach, plum pocket, etc. (Exoascus). 



445. Order Helvellales (Helvellineae). The asci form large fields over 

 the upper portion of the fruit body. This order includes the morels (fig. 

 2310), helvellas, earth tongues (Geoglossum), etc. 



446. Order Pezizales (Pezizineae). The asci form a definite field or 

 fruiting surface surrounded on the sides and below by a wall of fungus tis- 

 sue, forming a fruit body in the shape of a cup. These are known as the 

 cup fungi (Peziza, Lachnea, etc.). 



447. Ord>r Phacidiales (Phacidiineae). Fungi mostly saprophytic, and 

 fruit body similar to the cup fungi. Examples: Propolis in rotting wood, 

 Rhytisma forming black crusts on leaves (maple for example), Urnula 

 craterium, a large black beaker-shaped fungus on the ground. 



448. Order Hysteriales (Hysteriineae). Fungi with a more or less elon- 

 gated fruit body with an enclosing wall opening by a long slit. In some 

 forms the fruit body has the appearance of a two-lipped body; in others 

 it is shaped like a clam shell, the asci being inside. Example, Hystero- 

 graphium common on dry, dead, decorticated sticks. 



449. Order Tuberales (Tuberineae). The more or less rounded fruit 

 bodies are usually subterranean. The most important fungi in this order 

 are the truffles (Tuber). The mycelium of many species assists in the 

 formation of mycorhiza on the roots of oaks, etc., and several species are 

 partly cultivated, or protected, and collected for food. This is especially 

 the case with Tuber brumale and its forms; more than a million francs 

 worth of truffles are sold in France and Italy yearly. Dogs and pigs are 

 employed in the collection of truffles from the ground. 



450. Order Plectascales (Plectascineae). The fruit body of these plants 

 is more or less globose, and contains the asci distributed irregularly through 

 the mycelium of the interior. Some are subterranean (Elaphomyces), 

 while others grow in decaying plants, or certain food substances (Euro- 

 tium, Sterigmatocystis, Penicillium). Penicillium in its conidial ^tage 

 forms blue mold on fruit, bread, etc. 



The following four orders comprise the Pyrenomycetes, according to the 

 usual classification. 



451. Order Perisporiales. The powdery mildews are good examples of 

 this order (Uncinula, Microsphffira, etc., Chapter XXI). 



