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PLANT STUDIES 



large one, and contains a great variety of forms. All of 

 them, however, produce spores in asci, but the asci are not 

 always inclosed by an ascocarp. Here belong the common 

 blue mould {Penicillium) found on bread, fruit, etc., in 

 which stage the branching chains of conidia are very con- 

 spicuous (Fig. 243) ; the truffle-fungi, upon whose subter- 



Fig. 243. Penicillium, a common mould : A, mycelium with numerous branching 

 sporophores bearing conidia ; B, apex of a sporophore enlarged, showing branch- 

 ing and chains of conidia. — After Bhefeld. 



ranean mycelia ascocarps develop which are known as 

 " truffles " ; the black fungi, which form the diseases known 

 as " black knot " of the plum and cherry, the " ergot " of 

 rye (Fig. 244), and many black wart-like growths upon the 

 bark of trees ; other forms causing " witches'-brooms " (ab- 

 normal growths on various trees), "peach curl,*' etc., the 

 cup-fungi (Figs. 245, 246), and the edible morels (Fig. 247). 



