242 



Mycologia 



Rosellinia Rosarum Niessl 

 On dead branches of Rosa (14763 p.p.). 



Hyalodidymae 

 Mycosphaerella Iridis (Awd.) Schrot. 

 On leaves of Iris tnissouriensis Nutt. (13615). 



Mycosphaerella tingens Niessl? 



On old leaves of Arenaria Fendleri Gray (14363 a). 



Asci 67X17/*; sporidia oblong, rounded at the ends, uni- 

 septate, one cell narrower, greenish hyaline, 24 X 6-7 fi. The 

 spores are larger than those in the description and the discolored 

 spots on the leaves are rarely present. 



Mycosphaerella pachyasca Rostr. 



On old stems of Agoseris (13731) and on old leaves of Mer- 

 tensia caelestina Nels. & Cockerell. 



Mycosphaerella Primulae (Auersw. & Heufl.) Schrot. 

 On old stems of Androsace diffusa Small (14174). 



Didymella nigrescens Dearness & Fairman sp. nov. 



Perithecia black, shining on the summit, rather thickly scat- 

 tered in the darkened surface of the decorticated branchlets, 

 conoid or depressed-globose, base thin or almost disappearing, 

 sunk in the unaltered wood, the ostiolum only, or up to half of 

 the wall, erumpent, .25-4 mm. in diam. ; ostiola minute, round, 

 often in an umbilicate depression; asci clavate-cylindric, obtuse at 

 apex, short-stipitate, 8-spored, 65-90 X 7-10 fx; paraphyses simple, 

 abundant, longer than the asci ; spores hyaline, inequilateral, 

 oblong-fusoid, biseriate above, i-septate, constricted, upper cell 

 larger, sometimes a gutta in each cell, 10-13 X 3-5-4-5 



On old branches of Symphoricarpos oreophilus Gray (14754 

 p.p.). 



