50 



The North American Cup-Fungi 



tinia Rhododendri Fischer) in which heterocism is said to occur 

 and in which the conidial stage occurs upon one host and the 

 pseudosclerotial and apothecial stages upon another host. 



"(2) Those members in which ascospores normally infect 

 blossoms, upon which conidia then develop and function as 

 inoculum for secondary cycles on fruits (chiefly). Pseudosclero- 

 tia develop within infected fruits, overwinter upon the ground 

 and give rise to apothecia, thus furnishing ascosporic inoculum 

 for blossom infection in the spring. Commonly many successive 

 secondary cycles may occur. In this subgroup the sweetish 

 odor is not evident, disjunctors between the conidia are lacking, 

 and the members appear to be less specialized as to host. North 

 American representatives of this group are MoniUnia fructicola 

 and Monilinia laxa. 



"All known members of this genus occur as parasites on mem- 

 bers of the three following families of plants: the Rosaceae, the 

 Cornaceae, and the Ericaceae." 



On plants of the family Rosaceae. 

 On plants of the genus Primus. 



Conidial stage forming brown spots on fruit. 

 Conidial stage Monilia cinerea americana. 

 Conidial stage Monilia cinerea. 

 Conidial stage not forming brown-rots. 

 Conidia large, 10-20 n long. 

 Conidia medium 7-15 /x long. 

 On Pruniis serolina. 

 On Prumis demissa. 

 Not on Primus. 

 On Amelanckier. 

 On Crataegus. 



Ascospores 6-8 X 12-15 ju- 

 Ascospores 2-3.5 X 8-12 /x. 

 On plants of the family Ericaceae. 

 On Polycodium. 

 On Vaccinium. 

 On blueberry. 



1. M. fructicola. 



2. M. laxa. 



3. M. Padi. 



4. M. Seaveri. 



5. M. demissa. 



6. M. Amelanchieris. 



On cranberry. 

 On Azalea. 



1. Monilinia fructicola (Wint.) Honey, Mycologia 20: 



1928. (Plate 83.) 

 Cz6ona/rMC<ico/a Winter, Hedwigia 22: 131. 1883. 

 Sclerotinia fructicola Rehm; Sacc. Syll. Fung. 18: 41. 1906. 

 Monilia cinerea forma americana Wormald, Ann. Bot. 34: 168. 1920. 

 Sclerotinia americana Norton & Ezek. Phytopathology 14: 31. 1924. 



153. 



