A STUDY OF AUTUMN WEEDS 23 



cc Flower clusters in axils of leaves 



d A tall erect plant with woolly leaves Horehound 



dd A low plant with small smooth leaves Pennyroyal 



aaa With neither onion nor mint ordor; leaves much 

 dissected, fernlike 



b Flowers white in flat-topped clusters Western Yarrow 



bb Flowers yellow 



c In flat-topped clusters Tansy 



cc In daisy-like heads; odor disagreeable 



d Head ^-inch across Dog Fennel 



dd Head larger Stinking Willie 



VII. Weeds with simple leaves that are opposite 

 a Leaf edges entire 



b Fruit a berry inclosed in a balloon-like calyx 



(for species see Gray, p. 714) Ground Cherry 



bb Fruit not a berry 

 c Flowers red 



d Leaves heart-shaped Umbrellawort 



dd Leaves lance-shaped; calyx lobes extend- 

 ing beyond corolla Corn Cockle 

 ddd Leaves linear Red Campion 

 cc Flowers orange Butterfly Weed 

 ccc Flowers pink; in terminal clusters Soapwort 

 cccc Flowers white, looking like pinks White Campion 

 ccccc Flowers blue, looking like pinks Ragged Robin 

 aa Leaf edges toothed or lobed 

 b Stem not square 



c Leaves deeply palmately cut 



d Almost compound; lobes linear Wild Hemp 



dd Lobes broad Giant Ragweed 



cc Leaves only toothed 



d Leaf base heart-shaped; plant provided 



with stinging hairs Stinging Nettle 



dd Leaf base not heart-shaped; no stinging 

 hairs; small flower clusters with white ray 

 flowers Galinsoga 



bb Stem square 



c Blue flowers in terminal spikes Vervain 



VIII. Weeds with simple leaves; the leaves alternate 

 a Leaves with entire edges 



b Leaves linear or very narrow 

 c Plants with yellow flowers 

 d Flowers good sized 



e Flowers spurred, two-lipped Butter and Eggs 



