IOWA ACADEMY OF SCIENCE 
39 
Macbride informed the writer that he collected the same during the 
fall of 1886 at which time there was an abundance. It covered the 
entire north side of a tree 40 feet high. A quantity was collected 
but most of it was afterward found missing. No special effort has 
since been made to collect it. 
The variety is based on the appendages which are markedly dif- 
ferent from those of the type. Profs. Macbride and Peck agreed 
upon the name Pliyllactinia suffulta tomentosa for the variety. It 
seems that corylea rather than suffulta is the name that should be 
applied to the species and is so published here. 
The occurrence of this variety and the circumstances under which 
it was found are rather remarkable. Its taxonomic position is a 
puzzle. The appendages are so different from those of the typical 
P. corylea that it might be considered a distinct species if it could 
be shown that these differences were constant. On the other hand 
it may simply be a sport due to some peculiarities of host plant and 
season. Several facts seem to lend color to the latter view. 
HOST INDEX. 
Abbreviations used: E., Erysiphe; M., Microsphaera; Ph., Phyllactinia; 
Po., Podosphaera; S., Sphaerotheca ; U., Uncinula. 
For those marked ? see pages. 
Acer saccharinum L U. circinata 
Acer saccharinum Wang. See A. saccharinum Marsh. 
Acer saccharum Marsh U. circinata 
Acer dasycarpum Ehrh. See A. saccharinum L. 
Actinomeris squarrosa Nutt. See Verbesina alter ni folia. 
Adicea pumila (L.) Raf E. cichoracearum 
Agrimonia eupatoria L. See A. hirsuta. 
Agrimonia hirsuta (Muhl.) Bicknell S. humuli 
Alnus rugosa (DuRoi) K. Koch M. alni 
Alnus serrulata Wilid. See A. rugosa. 
Ambrosia artemisiae folia L E. cichoracearum 
Ambrosia psilostachya DC E. cichoracearum 
Ambrosia trifida L E. cichoracearum 
Ambrosia trifida integrifolia (Muhl.) T. & G E. cichoracearum 
Ampelopsis quinquefolia Michx. See Parthenocissus quinquefolia. 
Amphicarpa pitcheri T. & G. See Falcata pitcheri. 
Anemone canadensis L E. polygoni 
Anemone pennsylvanica L. See A. canadensis. 
Anemone sp E. polygoni 
Anemone virginiana L ....E. polygoni 
Anemonella thalictroides Spach. See Syndesmon thalictroides. 
Artemisia biennis Wilid E. cichoracearum 
Artemisia gnaphaloides Nutt E. cichoracearum 
Artemisia serrata Nutt E. cichoracearum 
