216 



Mycologia 



The pycnidia vary in form; the majority are oblong or elliptical, 

 while some are lobed or notched. In all a central ostiole is 

 present (Figs. 2, 3). 



The spores are three-septate and either clear or slightly smoky, 

 and each terminal cell bears a straight or slightly curved cilium 

 a little longer than half the length of the spore. In many of the 

 spores the two terminal cells are quite clear, and less granular 

 than the two middle cells. The spores are comparatively uni- 

 form in diameter, and nearly straight, with a slight curvature on 

 the side directed away from the cilia. The length varies from 

 12 to 20 /x but the diameter shows no appreciable variation, never 

 exceeding 2.6^ (Figs. 4, 5). The detail of the spore formation 

 as represented in cross-sections of the pycnidia shows the spore- 

 bearing branches as straight, unbranched hyphae with spores erect 

 and packed closely together (Fig. 6). 



The parenchymatous condition of the pycnidium wall is very 

 apparent in the basal portion but less so in the superficial portion. 

 A characteristic and well-marked feature of the pycnidium is 

 the occurrence of vertical supporting columns of hyaline hyphae 

 which run from the floor of the pycnidium to the roof, and 

 serve to retain the wall of the pycnidium in its original position 

 until the spores have escaped (Fig. 7). 



The following technical description of this fungus is appended : 



Discosia Pini sp. nov. 



Peritheciis sparcis vel subgregariis, superficialibus, applanatis, 

 nigris, opacis, glabris, ostiolo subpertusis ; ellipticis vel leniter 

 lobulatis, 225-362 120-165 ^ ; sporulis oblongo-fusiformis, 3- 

 septatis, hyalinis vel leniter fumagineis, 12-20 = 2.6 /x, 2-ciliatis, 

 10-12 /jl longis (pi. 14, f. 1-7). 



Ad hypocotylem viventem Pini ponderosae, Forest Reserve, 

 Halsey, Nebraska. 



Type specimen, No. 758, Herb. Dept. Agric. Bot., Univ. of 

 Nebraska, Lincoln, Nebraska. 



Department of Botany, 

 University of Texas. 



