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IOWA ACADEMY OF SCIENCE Voi.. XXVIII, 1921 
Brassica arvensis 
Cystopus candidus (Pers.) Eev. 
Brassica campestris 
Peronospora parasitica (Pers.) 
Tul. 
Brassica nigra 
Cystopus candidus (Pers.) Eev. 
Peronospora parasitica (Pers.) 
Tul. 
Capsella bursa-pastoris 
Cystopus candidus. (Pers.) Eev. 
Peronospora parasitica (Pers.) 
Tul. 
Cerastium nutans 
Peronospora alsinearum Caspary 
Chenopodium sp. 
Peronospora effusa (Grev.) 
Rabh. 
Chenopodium album 
Peronospora effusa ' (Grev.) 
Rabh. 
Draba Caroliniana 
Peronospora parasitica (Pers.) 
Tul. 
Echinocystis lobata 
Plasmopara australis (Speg.) 
Swingle 
Eupatorium purpureum 
Plasmopara Halstedii (Farl.) B. 
and dT. 
Euphorbia maculata 
Peronospora euphorbiae Fckl. 
Euphorbia Preslii 
Peronospora euphorbiae Fckl. 
Euphorbia serpyllifolia 
Peronospora euphorbiae Fckl. 
Erigeron sp. 
Plasmopara Halstedii (Farl.) B. 
and dT. 
Galium aparine 
Peronospora calotheca D.By. 
Galium boreale 
Peronospora calotheca D.By. 
Geranium Carolinianum 
Plasmopara geranii (Pk.) B. 
and dT. 
Geranium maculatum 
Plasmopara geranii (Pk.) B. 
and dT. 
Gonolobus laevis 
Peronospora gonolobia Eagerh. 
Helianthus annus 
Plasmopara Halstedii (Farl.) 
B. and dT. 
Helianthus doronicoides 
Plasmopara Halstedii (Farl.) B. 
and dT. 
Helianthus grosse-serratus 
Plasmopara Halstedii (Farl.) B. 
and dT. 
Helianthus Maximiliani 
Plasmopara Halstedii (Farl.) B. 
and dT. 
Helianthus tuberosus 
Plasmopara Halstedii (Farl.) B. 
and dT. 
Hydrophyllum Virginianum 
Peronospora hydrophylli Waite. 
Impatiens biflora 
Peronospora obducens Schrot. 
Impatiens pallida 
Peronospora obducens Schrot. 
Ipomoea batatas 
Cystopus ipomeae-panduranae 
(E) Farl. 
Eactuca sp. 
Bremia lactucae Regel. 
Eactuca ludoviciana 
Bremia lactucae Regel. 
Eactuca leucophoea 
Bremia lactucae Regel. 
Eaportea canadensis 
Peronospora urticae (Eib.) D. 
Bv. 
Eepidium apetalum 
Peronospora parasitica (Pers.) 
Tul. 
Cystopus candidus (Pers.) Eev. 
Eepidium Virginicum 
Cystopus candidus (Pers.) Eev. 
Peronospora parasitica (Pers.) 
Tul. 
Medicago sativa 
Peronospora trifoliorum D.By. 
Monarda balsamina 
Peronoplasmopara cubensis (B. 
and C.) Cl. 
Monarda sp. * 
Synchytrium Holwayi Farl. 
Montelia tamariscina 
Cystopus bliti (Biv.) D. By. 
Oenothefa biennis 
Peronospora Arthuri Farl. 
Panax quinquefolium 
Phytophthora omnivora D. By 
Parthenium integrifolium 
Cystopus tragopogonis (Pers.) 
Schrot. 
Plantago major 
Peronospora effusa (Grev.) 
Rabh. 
Peronospora alta Fckl. 
Plantago Rugelii 
Peronospora polygon! Thuem. 
Polygonum aviculare 
Peronospora polygon! Thuem. 
Polygonum scandens 
Peronospora polygon! Thuem. 
Portulaca oleraceae 
Cystopus portulacae (D. C.) Eev. 
Potentilla monspeliensis 
Peronospora potentillae D.By. 
Prenanthus albus. 
Bremia lactucae Regel. 
