332 CLASS ASCOMYCETEAE 



close relationship to the Pezizales. Whether the order should be con- 

 sidered to consist of but one family or of several depends upon the weight 

 given to the arrangement of the asci in the spore fruit, i.e., in a single layer 

 or scattered at various depths below the outer surface, and to the septa- 

 tion and color of the ascospores. Until life-history studies like those by 

 Miller have been completed on the other genera of this order it seems 

 advisable for the present to include all in one family. 



Family Myriangiaceae. Julian Miller (1938) described in detail the 

 development of the ascocarps of two species of Myriangium and con- 

 cluded that this genus, and the other genera usually associated with 

 it in this family, are not properly ''Pyrenomycetes" but on the con- 

 trary should be associated with the Aspergillales. The species of this 

 genus are parasitic upon scale insects which in their turn are feeding upon 

 many kinds of trees and shrubs in the tropical and warm temperate re- 

 gions of the world. Growing out from the body of the host the mycelium 

 forms a firm cushion-like stroma which is rather strongly anchored to the 

 bark of the host by hyphae that may penetrate the lenticels. That there 

 may be some direct parasitism upon the woody host is suggested by the 

 fact that the bark cells underneath the center of the stroma die. Further- 

 more a stroma may remain alive and produce ascocarps for several years, 

 long after the scale insect has been killed by the fungus. At the central 

 thicker portion of the stroma arise the archicarps just under the upper 

 surface. These are upright, more or less coiled, hyphae of uninucleate 

 cells (as are all of the cells of the stroma), the upper cell being attenuated 

 and one or more of the middle or lower cells enlarged and soon multi- 

 nucleate. Accompanying the archicarp is a more or less loosely coiled 

 hypha of slender uninucleate to plurinucleate cells, apparently the an- 

 theridial hypha. However, no connection between antherid and archicarp 

 was observed. No spermatia were produced anywhere in the stroma. The 

 enlarged ascogonial cells divide repeatedly producing a layer of large 

 multinucleate cells. From the apex of each such cell arises an ascogenous 

 hypha of binucleate cells. Thus is produced a flat or concave disk-like 

 thickening on the stroma consisting entirely of parallel, closely packed 

 ascogenous hyphae. These are more or less branched. Terminal and inter- 

 calary cells of these hyphae divide longitudinally or diagonally. The two 

 nuclei of one of these daughter cells divide again and two septa are formed, 

 producing a row of three cells, the central one binucleate. These two nuclei 

 unite and the cell enlarges to become the ascus. Since many cells in each 

 ascogenous hypha may produce asci and these hyphae are packed side by 

 side to form the disk of the ascocarp the resultant asci are scattered at 

 various depths below the upper surface but are separated by the tissues 

 consisting almost entirely of ascogenous hyphae. There is no dissolution 

 to form monascous cavities such as is found in the Pseudosphaeriales. 



