34 
IOWA ACADEMY OF SCIENCE 
Amphigenous; mycelium subpersistent or sometimes evanescent; perithecia 
85-145 micra in diameter, rarely larger, cells 10-15 micra wide, appendages 7-28, 
2 V 2 -8 times the diameter of the perithecium, flexuose, often angularly bent, 
colorless, aseptate, apex 3-4 times dichotomously branched, branching irregu- 
lar and lax, tips straight or recurved; asci 4-13, rarely more; short pedicel- 
late, 48-66x26-33 micra; spores usually 4 (3-6), 19-21x10-12 micra. 
On Euphorbia corollata, L. Decatur Co., Oct., 1904 and 1905 (Anderson) ; 
Decorah, Sept., 1879 (Hoiway) ; *Fayette, 1893 (Fink) ; Ringgold Co., Oct. 
7, 1905 (Anderson). 
On Euphorbia marginata Pursh. Johnson Co., 1888 (Macbride). 
As in some other species of Microspliaera the appendages are 
very slow in arriving at maturity, hence it is often collected with 
the appendages not yet branched. 
In August, 1905, I found this species in abundance on Euphorbia 
marginata in Cass County, Nebraska, but could find none on the 
east side of the Missouri River in Fremont County although the 
host was very abundant. 
Uncinula Lev. 
Perithecium containing several asci, asci 2-8 spored; appendages free from 
the mycelium, uncinate or coiled at the apex. 
Key to Iowa Species of Uncinula. 
Appendages colored 2. U. necator 
Appendages hyaline or nearly so. 
Asci 2 spored 5. U. macrospora 
Asci 4-8 spored. 
Appendages delicate, narrow, 3-4 micra wide, asci 4-7 spored. 
Appendages 50-160, %-% times the diameter of the perithecium 
4. U. parvula 
Appendages 24-46, l%-2 times the diameter of the perithecium 
7. U. geniculata 
Appendages stouter. 
Appendages thick walled, refractive at base 6. U. clintoni 
Appendages thin walled. 
Asci 4-6 spored 1. U. salicis 
Asci 7-8 spored 3. U. circinata 
1. Uncinula salicis (DC.) Wint. 
Uncinula adunca, Lev. Bessey, The Erysiphei, and Prel. List, Ames Flora; 
Hitchcock, Partial List Iowa Powdery Mildews. 
Uncinula heliciformis E. C. Howe. Hitchcock, Partial List Iowa Powdery Mil- 
dews. 
Uncinula salicis (DC.), Wint. Fink, Blights, etc., of Fayette. 
Amphigenous; mycelium evanescent or persistent; perithecia 90-175 micra in 
diameter, cells 10-15 micra wide; appendages usually numerous or crowded, 100- 
