28 A Monograph of the Ervsiphaceae] 



List of new Species and Varieties 



Uncimda salicis, var. Miyabci, 

 Uncimda Fraxini. 

 Uncimda Scngohin. 

 Microsphacra alni^ var. ludois. 



ERVSIPHACEAE Lev. 



Parasitic on living (phanerogamic) plants ; vegetative mycelium 

 white, external to the host-plant, either [ErysipJicae) forming haus- 

 ^^ toria in the epidermal cells, or (^Phy I I actinie a e^ sending special 

 branches for a short distance through the stomata into the inter- 

 cellular spaces, and from these branches sending haustoria into the 

 surrounding cells ; hyphae thin-walled, septate, much-branched 

 and interwoven ; conidia large, continuous (non-septate), colorless 

 or white, cylindrical, oblong, or barrel-shaped, produced singly or 

 in concatenate chains in basipetal succession on erect, simple, 

 septate, colorless conidiophores ; pcrithecia arising directly from 



the mycelium, sessile, at first colorless, then yellow, becoming 

 finally brown or black, membranaceous, indehiscent, globose or 

 globose-depressed, sometimes becoming concave ; walls many- 

 layered, pseudo-parenchymatous, the apical, equatorial or basal 

 cells of the outer wall usually giving rise to definite outgrowths, 

 the appendages, which are either more or less similar to the mycelial 

 hyphae, or quite distinct from them, and variously shaped, simple or 

 branched at the apex, erect or radiating, sometimes colored ; asci 

 one or many, arising from the base of the perithecium, colorless, 

 cylindrical, oblong, ovate or globose, frequently pedicellate, 2-8- 

 spored ; spores continuous (non-septate), colorless, oblong or oval, 

 with obtuse ends, straight or rarely slightly curved ; paraphyses 



absent. 



Sub-family Erysipheae Palla. 



Mycelium wholly external to the tissues of the^host-plant ; 

 sending haustoria into the epidermal cells only. 



Key to llie Genera 



I. Ascus solitary. 



Asci several. 



'2. 



3- 



2. Appendages of the perithecium basal, sometimes obsolete, not branched in a definite 



manner at the apex. 



Sphaerotkeca, 



Appendages of the perithecium branched at the apex, or if unbranched, arising api- 

 cally. • Podosphaera, 



3. Appendages of the perithecium nearly always simple (branched in U, aceris (see 

 ■Fig. 87)), uncinate at the apex. Uncinula. 



Appendages not uncinate. a 



