78 



Mycologia 



voluted or verrucose, sometimes almost papillate, almost never 

 smooth. The tubercles are solidly attached to the bark by a nar- 

 rower, stipe-like portion which appears to penetrate through the 

 outer corky portion into the living phloem tissue. 



The inner portion of the tubercle is reddish-brown in color, and 

 is densely and uniformly pseudoparenchymatic in structure, with a 

 very thin, darker, crust-like layer on the outside. Occasionally 

 streaks of slightly darker, thicker-walled cells will be found ex- 

 tending through this uniform tissue. Such streaks are usually 

 located a short distance beneath the beginning of the loculiferous 

 region. This portion, in which the asci occur, lies near the pe- 

 riphery of the tubercle, just beneath the crust-like layer, and on 

 the outer side of each of the convolutions. 



The locules are closely crowded together, often being separated 

 by only one or two rows of the pseudoparenchymatous stromatic 

 cells. They are subglobose to broadly ovate or oval in form and 

 occur in several layers, some of the outer convolutions being almost 

 entirely loculiferous. In microtome section this portion of the 

 tubercle-like stroma has a very open, porous appearance. Even 

 when cut with a knife in the natural condition while still attached 

 to the tree, this locule-bearing tissue has a gray, powdery appear- 

 ance in contrast to the dark brick-red or brownish-black of the 

 solid, homogenous, sterile portion beneath it. ' 



Each locule is lined with a thick, hyaline sheath, inside which 

 occurs a single ascus. When the stroma is crushed and examined 

 under the microscope, this sheath easily separates from the tissue 

 of the stroma and remains about the ascus, giving the appearance 

 of being merely a very thick ascus wall. If the sheath becomes 

 ruptured, however, the ascus immediately expands, chiefly in a 

 longitudinal direction, often to two or two and one half times its 

 original length, becoming oblong, broadly spindleform, or ovate 

 with blunt rounded ends, while the ruptured locule sheath collapses 

 about its base. The ascus wall is quite thin as compared with this 

 sheath, except at the apical end, where it is heavily thickened. 

 There is no apical pore and the method of spore discharge has not 

 been observed. Since the locules are indehiscent, and the pore at 

 the apex of the ascus is absent, this probably is brought about by 



