130 IOWA ACADEMY OP SCIENCE 
Populus deltoides Marsh 128 
Portulaca oleracea L 8 
Potentilla canadensis L 122% 
Potentilla monspeliensis L 14, 19 
Prunus americana Marsh 17, 18, 27, 50, 71 
Prunus a,vium L 50, 71 
Prnnns besseyi Bailey 71 
Prnnns cerasns L 50, 71 
Prnnns domestiea L 17, 18, 27 
Prnnns hortnlana Bailey 18, 114 
Prnnns mahaleb L 50 
Prnnns triflora 18 
Prnnns virginiana L 27 
Puceinia graminis Pers 32 
Pyrus commnnis L 2, 3, 37% 
Quercns prinoides Willd. . . . ' 79 
Quercus rnbra L 77 
Ranunculus abortivus L 73, 149 
Raphanus sativns L 6 
Rhamnus lanceolatus Pursh 99 
Rhns glabra L 63 
Rhns toxicodendron L. 96 
Ribes missonriensis Nntt 38, 138 
Ribes rubrnm L. 58% 
Ribes sp 70, 138 
Roripa palustris (L.) Bess 6 
Rosa arkansana Porter 67, 124 
Rosa hemisphaerica Herrm 123 
Rosa multiflora Thunb 69 
Rubns canadensis roribaceus Bailey .38% 
Rnbns neglectns Peck 48 
Rubns nigrobaccns Bailey 2, 48, 122 
Rubns strigosus Miehx 2, 48 
Rum*ex sp 52 
Salix nigra Marsh 129 
Salix interior Rowlee 129 
Salomonia commntata (R. & S.) Britt 135 
Sanicula marylandica. L 40 
Scrophnlaria marylandica L 45 
Silene stellata (L.) Ait 41 
Silphium integrifolium Miehx 116, 134 
