IOWA ACADEMY OF SCIENCES. 181 



He first found the fungus late in November, 1892, on a few 

 belated leaves clinging to the adventitious shoots from the stump 

 of a young apple tree in Newfane, Vt. He has had access to 

 the material in the Ellis herbarium, and finds it represented 

 from Missouri (Demetrio), Kansas (Kellerman & Swingle). 

 Grant observes that this mildew is probably not uncommon, 

 but is rarely collected because its perithecia are on the shoots 

 instead of the leaves, and also because the perithecia do not 

 mature until very late in the autumn. In the Mississippi val- 

 ley the perithecia mature much earlier. They are common in 

 September, and some may be found in August. But our cli- 

 mate is so much drier than that of the New England states, 

 and this accounts for the early maturation of the perithecia at 

 Ames. 



So far as the writer knows the apple fungus occurring in Iowa 

 is Sjihcerotheca mali and not Podosphcera oxyacanthcB. Professor 

 Burrill, however, also reports the Podosphcern oxyacantJm on 

 Pyrus malus. This fungus may be characterized as follows: 

 Amphigenous, mycelium white or frequently slightly fuscous, 

 submembranceous, persistent. Perithecia few or numerous, 

 immersed in the mycelium; small; seventy-five to eighty -five 

 appendages of two kinds; one kind consists of one or more 

 dark, straight, jointed, occasionally forked at the end; the 

 other consists of short, colorless, floccose, rudimentary 

 appendages. Each perithecium has a single ascus which 

 usually contains six ascospores. This fungus occurs on the 

 leaves and stems in the nursery, especially sprouts around old 

 trees. In such places it is extremely abundant at times. It 

 is as abundant in Illinois as in Iowa. 



Professor Burrill in commenting upon this fungus says: 

 "This exceedingly interesting species has not been well 

 separated from Podosphcera oxyacantluE which occurs on the 

 same host and to casual observation has much the same 

 appearance. In our species the tips of the large appendages 

 are occasionally forked (once or even slightly twice), which 

 again may have been confusing. But these vague, stiff 

 branches are totally unlike the dichotomous divisions of Podos- 

 phcera, and otherwise the species are very distinct. The tuft 

 of short, interwoven rudimentary appendages, like a dense 

 cluster of short roots, is a very characteristic mark. " 



This fungus is of considerable economic importance. Mr. 

 Stewart writes me he has not commonly met with it in New 



