ASCOMYCETES 281 



the pear-shaped mass, three to six centimetres long, must 

 be considered as a fleshy stroma, bearing numerous asco- 

 phores embedded in its periphery. In some instances, as 

 the Sticteae, where the species are embedded in the matrix, 

 the ascophore is quite rudimentary. Other species em- 

 bedded in the substratum depart from the typical circular 

 disc or hymenium, and have an elongated or radiately 

 formed sporophore, which splits along its length ; the lips 

 of the split finally gape and expose the hymenium. 



As would be expected in such a large assemblage of 

 forms, the two groups closely approach each other at 

 certain points. Genera and even families have from time 

 to time been removed from one sub-order to another, 

 depending on individual opinion. 



The family Hysterieae has until quite recently been 

 considered as belonging to the Discomycetes. Saccardo, 

 however, has removed it to the Pyrenomycetes. The 

 sporophore is more or less elongated, or sometimes radially 

 branched, and the opening of what must be considered a 

 perithecium from Saccardo's point of view has an elongated 

 slit through which the spores escape. Now, technically, the 

 ascus-bearing surface or disc should remain perfectly con- 

 cealed in the Pyrenomycetes, whereas in many of the 

 Hysterieae the disc is partially exposed by the gaping of 

 the border or lips bounding the slit. Hysterieae is a 

 transition family, undoubtedly, and it was not worth the 

 trouble on Saccardo's part to remove it from one sub- 

 family to another. 



The genus Sphatrosoma is also a transition genus con- 

 necting the Tuberaceae with the Discomycetes. It has 

 the hymenial structure and asci of the Discomycetes, but 

 more or less of the general morphology and certain of the 



