Levine : Sporadic Appearance of Mushrooms 53 



Aleuria vesiculosa Bull, and Aleuria vesiculosa Bull. 

 Var. saccata Fr. 



Other fungi, which appeared in the mushroom houses around 

 New York about the same time, are shown in figures 5 to 10. 

 These plants appeared in the manure of newly made mushroom 

 beds. They were particularly abundant near the boards which 

 enclosed the beds made under the benches in a greenhouse. The 

 plants appeared in great clusters weighing from ^ to 2 lbs. 



These plants are typical mushroom cellar plants and have been 

 described and figured by Boudier.* 



Aleuria vesiculosa var. saccata is identical with Aleuria vesi- 

 culosa except for the hymenial surface, which in the former is 

 cerebriform as shown in figures 8 and 9. The spores also are 

 slightly different in size. In the early stages no difference could 

 be detected between them. The plants at this stage (Figures 5 

 and 6) are covered with a whitish-gray papillate structure which 

 disappears as the plants grow older, although the color of the 

 outer surface always remains lighter than the hymenium, which 

 is buff-brown in color. Great numbers of plants in this stage 

 appeared without showing any indication of a cerebriform hyme- 

 nium, although at slightly older stages shown in figures 7 and 8 

 the two forms can readily be distinguished. It has been assumed 

 that the manure and the soil used for casing are responsible for 

 the sporadic appearance of the non-edible mushrooms in the 

 mushroom cellars ; up to the present however no conclusive evi- 

 dence has been brought to bear on this subject and it may be sug- 

 gested that the so-called " Pure Spawn " is not beyond suspicion. 



Columbia University, 

 New York City. 



Explanation of Plate 4 



Figs, i, 2, 3, 4. Show the nature of the pileus, stipe, gills and general 

 habit of fungus described in text. (Natural size.) 



Figs. 5, 6. Young stages in the development of Aleuria vesiculosa Bull. 

 (Natural size.) 



4 Boudier, E. Icones Mycologicae 2: pi. 257-258. 4: p. 139. 



