Durand : Classification of the Fleshy Pezizineae 481 



The hypothecium is a thick layer composed of small rounded 

 cells about 3 /i in diameter, very closely compacted and obscured 

 by granules. Toward the base and sides of the cup this tissue 

 passes into one composed of larger polygonal cells, 6—10 // in 

 diameter, making up the excipulum. The outer excipular cells 

 give rise near the margin to the pili, which are much prolonged, 

 thick-walled cells of this layer. In my sections the excipular 

 cells continue fully to the surface without any limiting membrane. 

 The cup is fixed at the base by hyphae continuous with the basal 

 cells of the excipulum. 



Ascobolus furfuraceus Pers. 



The structure of the sterile layers of this plant closely resem- 

 bles that of the preceding. The cells are generally much larger, 

 while one or two layers at the surface form a more or less distinct 

 ectal membrane. 



Family HELOTIACEAE 



Sclerotinia pseudotuberosa Rehm. PL 31, Fig. 11 



This is a small plant with a long slender stem growing on 

 acorns. The waxy cup is reddish-brown within, but greenish- 

 brown without. The sterile part of the plant exhibits three well- 

 defined areas. The subhymenial area, or hypothecium, is a thin 

 layer of very slender, closely interwoven hyphae, perhaps 1-2 ft 

 in diameter. In the center of the cup the layer is well defined, 

 but toward the margin it is lost by becoming blended with the ex- 

 cipulum. 



The excipulum is composed of two layers. The inner or 

 medullary one fills the whole central part of the stem and cup. It 

 is made of extremely slender interlacing hyphae, which are looser 

 than those of the hypothecium. The tissue is lost as it approaches 

 the margin of the cup. The outer layer of the excipulum closely 

 resembles the hypothecium, and it is composed of intricately inter- 

 woven hyphae. It forms an ectal membrane of uniform thickness 

 covering the whole outer part of the stem and cup, and makes up 

 the margin of the latter. 



