790 WEED FLORA OF IOWA 



BLOOMING PERIOD OF COMMON WEEDS— Concluded. 



Setaria verticillata A. Whorled foxtail 



Setaria viridis A. Green foxtail 



Silene noctiflora A. Night-flowering catchfly 



Solanum nigrum A. Night-shade 



Sonchus arvensis P. Field thistle 



Saponaria officinalis P. Bouncing Bet 



Stipa spartea P. Needle grass 



Strophostyles helvola A. Wild pea 



Symphoricarpos orbiculata P. Indian currant 



Tanacetum vulgare P. Tansy 



Lactuca scariola A. Prickly lettuce 



Hibiscus trionum A. Shoo-fly 



Urtica dioica P. Stinging nettle 



Vernonia fasciculate/, P. Iron-weed 



Abutilon theophrasti A. Velvet leaf 



Amaranthus retroflexus A. Tumbling pigweed 



Aristida dichotomy A. Poverty grass 



Artemisia biennis B. Wormwood 



Artemisia ludoviciana P. Western mugwort 



Aster multifloris A. Many-flowered aster 



Aster salicifolius A. Willow-leaved aster 



Bidens aristosa A. or B. Sticktight 



Cenchrus tribuloides A. Sandbur 



Chenopodium ambrosioides A. Mexican tea 



Cirsium altissimum B. Tall thistle 



Cirsium eanescens B. Woolly thistle 



Cyperus esculentus P. Northern nut grass 



Dalea alopecuroides A. Foxtail dalea 



Digitaria sanguinalis A. Crab grass 



Echinochloa crusgalli A. Barnyard grass 



Helianthus grosseserratus P. Wild prairie sunflower 

 Helianthus maximiliani P. Maxmilian's sunflower. 



Helenium antumnale P. Sneezeweed 



Muhlenbergia mexicana P. Mexican dropseed 



MuhTenbergia racemosa P. Dropseed grass 



Solidago canadensis P. Canada goldenrod 



Solidago rigida P. Stiff goldenrod 



Solidago serotina P. Goldenrod 



Panicum capillar e A. Hair grass 



Sporobolus neglectus A. Small rush grass 



Sporobulus vaginiflorus A. Sheathed rush grass... 



Xanthium canadense A. Cocklebur 



Xanthium spinosum A. Spined cocklebur 



Helianthus tuberosus P. Artichoke 



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