60 



PLANT STKDCTURES 



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. 43) ; the truffle-fungi, upon whose subter- 



PiG. 43. 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 Brefeld. 



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. 44), 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. 45, 46), and the edible morels (Fig. 47). 



