HELOTIALES (INOPERCULATES) 251 



Helotiales {Ino per dilates) 



The Helotiales include nearly all the inoperculate Discomy- 

 cetes, except those that are symbiotically associated in the Liche- 

 nes. Nannfeldt (1932), it has been pointed out, divided this 

 order into 6 families, and in the present account brief mention 

 will be made of representative members of 4 of these families, 

 namely, Dermateaceae, Phacidiaceae, Helotiaceae, and Geoglos- 

 saceae. 



Nannfeldt characterizes the Dermateaceae as having apothecia 

 that are leathery to fleshy and typically dark. They arise either 

 at the surface or within the substratum and are sessile or, at most, 

 have a short stipe. They are paraphysate, and the ascospores are 

 hyaline and filamentous. 



The apothecia of the Phacidiaceae arise within a well-devel- 

 oped stroma that is usually dark. They open by an irregular rup- 

 ture of the stromatic covering. The ascospores are elongate to 

 needle-shaped. The excipulum is poorly developed. The conid- 

 ial stages of many of the Phacidiaceae belong to the Lepto- 

 stromataceae. 



In the Helotiaceae the apothecia are typically soft, fleshy to 

 corneous, superficial, and stalked. The excipulum is thick. The 

 ascospores are elliptical to elongate. Paraphyses are present. The 

 conidia belong to various form genera. 



The apothecia of the Geoglossaceae are club-shaped or stalked, 

 w^th a capitate hymenial surface. The ascospores are elongate to 

 thread-like, simple or septate, and none is known to possess a 

 conidial stage. 



Dermateaceae. This family is divided by Nannfeldt (1932) 

 into 9 tribes. The apothecia of all arise innately and at maturity 

 rupture the overlying tissues. They are corneous to leathery in 

 texture, and the excipulum is thick, being composed of dark, 

 thick-walled cells. 



Among the Mollisioideae is the Genus Pvrenopeziza, of which 

 one species, P. inedicaginis, produces the yellow leaf blotch of 

 alfalfa [Jones (1918)]. Its conidial stage was first described by 

 Desmazieres in 1 847 as Sporonema phacidioides. It appears rather 

 to be Phyllosticta. Jones was able to establish the genetic con- 

 nections of conidial and ascigerous stages, both of which devel- 

 oped in cultures on alfalfa stems and on oatmeal agar. 



