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IOWA ACADEMY OF SCIENCE 
or hoary appearance, from the presence of this mildew. It had 
not been observed previously and the Heliopsis scahra seen in Fre- 
mont County and eastern Nebraska in 1905 was not affected. 
E. M. Freeman in Minnesota Botanical Studies XXIV, reports 
Erysiphe cichoracearum on Heliopsis scabra. It is quite probable 
that this was the species' under consideration. 
Microsphaera Lev. 
Perithecia globose to globose depressed; asci several, 2-8 spored; append- 
ages free from the mycelium ; more or less dichotomously branched at the apex. 
Key to Iowa Species of Microsphaera. 
Tips of appendages recurved when mature. 
Appendages short, K-2 Vz times the diameter of the perithecium. . . .1. M. alni 
Appendages long, 2% -8 times the diameter of the perithecium. 
Apex much branched, ornate, spores 22-26x12-15 micra. . . .3. M. alni extensa 
Apex less branched, spores 18-23x9-13 micra 2. M. alni vaccinii 
Tips of appendages not recurved when mature. 
Appendages colored 6. M. russellii 
Appendages hyaline or nearly so: 
Appendages long, 2-7 times the diameter of the perithecium, contorted and 
angularly bent, branching irregular and lax 7. M. euphorbiae 
Appendages, 2-4 times the diameter of the perithecium, branching lax 
5. M. diffusa 
Appendages, 1-2 times the diameter of the perithecium, branching close and 
regular 4. M. grossulariae 
Microsphaera alni (Wallr.) Wint. 
Microsphaera alni (Wallr.), Wint. Fink, Blights, etc., of Fayette. 
Microsphaera abbreviata Peck. Bessey, The Erysiphei. 
Microsphaera densissima (Schwein.), C. & P., Bessey, The Erysiphei. 
Microsphaera friessi Lev. Bessey, Prel. List Ames Flora; Hitchcock, Par- 
tial List Iowa Powdery Mildews. 
Microsphaera hedwigii Lev. Bessey, The Erysiphei; Hitchcock, Partial List 
Iowa Powdery Mildews. 
Microsphaera menispermi E. C. Howe. Bessey, The Erysiphei. 
Microsphaera platani E. C. Howe. Bessey, The Erysiphei. 
Microsphaera pulchra Cook & Peck. Bessey, The Erysiphei. 
Microsphaera ravenellii Berk. Bessey, The Erysiphei. 
Microsphaera semitosta Berk & Curt. Bessey, The Erysiphei. 
Microsphaera quercina (Schwein.), Burr, in part. Fink, Blights, etc., of Fay- 
ette. 
Amphigenous; mycelium variable, evanescent or persistent, sometimes form- 
ing definite patches; perithecia scattered or gregarious, 66-110 micra in diameter, 
sometimes larger; cells 10-15 micra wide; appendages 4-26, lf-2% times the 
diameter of the perithecium, rigid, sometimes colored at the base; apex various- 
ly but closely, 3-6 times, dichotomously branched; tips recurved; asci 3-8, 
42-70x32-50 micra; spores, 4-8, 18-23x10-12 micra. 
