[O lujc.irrs, orchids and PERNS 



SO abundant very carefully next .summer, searching especially for 

 mycelium, and in this way I expect to get at the real solution of what 

 seems to be an unusual find. 



Podosphaera, Km, ; 



Perithecium containing a single ascus; appendages free from the mycelium, 



dichotomously branched at the end. 



I. P. OXYACANTHiE, (DC.) Duby. 



Amphigenous. Mycelium variable, often abundant, persistent, perithecia 65- 

 110 //, dark, opaque, reticulations regular, about 10-15 //, evident when young, scarcely 

 observable u lien old, except by the uneven surface; appendages 8-20, dark brown for 

 more than half their length, frequently septate, 1-4 times as long as the diameter of 

 the perithecium, 3-5 times dichotomously forked, branches short, often swollen, tips 

 recurved; ascus broadly elliptic or orbicular, about 50-60 u, thick walled; sporidia 

 usually 8. 



On Primus sp. 



This is a widely varying species. In my specimens, the appendages 

 are not branched and arise from the upper surface. They appear some- 

 what like those of S. Mali. 



Microsphsera, Lev 



Perithecium containing several asci; appendages free from the mycelium, more 

 or less dichotomously branched at the end. 



1. M. RUSSELUI, Clinton. 



Amphigenous. Mycelium inconspicuous; perithecia small, 75-100 //, delicate, 

 reticulations regular, distinct, about 10 //; appendages 8-18, many times longer than 

 the diameter of the perithecium, colored for half or two-thirds of their length, oc- 

 casionally septate, simple, bifid, or twoor three times irregularly branched, branches 

 long, often aistorted, tips not swollen or recurved; asci 4-8; sporidia usually 4, small. 



On Ox a lis cor mcu lata, var. stricta. 



I did not find any appendages that were branched. 



2. M. Euphorbia, (Peck.) B. & C. 



Amphigenous. Mycelium abundant, presistent; perithecia scattered, abundant, 

 usually small. 80-100 //, but olten larger (120 //), texture soft, elastic, reticulations 10- 

 15 it, frequently obscure; appendages 15-20, very long, 5-6, or more times the diameter 

 of the perithecium, hyaline, often slightly tinted at base, irregularly flexuous and 

 often nodularly swollen, at first simple, then part of them bifid or three or four times 

 dichotomous, branches long, lax, tips sometimes bifid, but not swollen or recurved; 

 asci 4-8, frequently 6, pedicellate, 35-40 by 65 n\ sporidia 4-6. 

 On Euphorbia corollata. 



On the College campus. Only four or five perithecia were found 

 fully developed though the collection was quite large. Consequently, 

 no specimens were sent away to be examined though I do not find this 

 recorded in Iowa lists, 



3. M. Alni, (DC.) Winter. 



Amphigenous. Mycelium often delicate and evanescent, sometimes abundant 

 and presistent; perithecia usually small, 75-100 u, sometimes large, 100-130 //, wall 

 tissue compact, rather fragile, reticulations not large, 10-15 u\ appendages 6 or 8 to 15 

 or 20, hyaline, usually tinted at base, often somewhat roughened, usually about 

 equaling, but varying from less than to more than twice the diameter of the perithe- 

 cium, 4-6 times dichotomous, branches varying in length and angle of divergence, 

 but always regular and symmetrical, tips acute, distinctly, often strongly, recurved; 

 asci varying with the size of the perithecium from 2 or 3 to 8 or more, usually 4 or 5, 

 ovate when numerous, suborbicular when few: sporidia 4-8, variable, mostly small, 

 averaging about 20 11 long. 



On Syringa vulgaris, Cory/us Americana, Ulmus Americana, 

 Viburnum lentago, Carpinus Caro/iniana, and Lonicera Sullivantii. 



