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A FIELD GUIDE IN NATURE-STUDY 



aaa Fruit not spiny; only stem or stem and leaves 

 spiny 

 b Flowers conspicuous 



c Flowers clustered in heads Thistles 



d Heads of bloom small, |-inch diameter Canada Thistle 



dd Heads of bloom large 



e Bracts on flower head spreading and 



prickly; leaves decurrent on stem Bull Thistle 



ee Bracts on flower head appressed, inner 

 not prickly 



/Leaves whitish above, plant low Shore Thistle 



//"Leaves creamy, woolly Pitcher's Thistle 



/(/"Leaves greenish above 



g Stem of flower head leafy, plant 



stem furrowed Roadside Thistle 



gg Stem of flower head not leafy 



h-*- Stem high Swamp Thistle 



hh Stem low Pasture Thistle 



cc Flowers solitary, violet, star-shaped; fruit 



an orange berry; stem with yellow spines Horse Nettle 



bb Flowers inconspicuous 



c Stem grooved; spines at base of leaves Spiny Amaranth 



cc Stem streaked with red; leaves spiny Russian Thistle 



VI. Weeds with strong odor 

 a Odor of onion 



b Leaves nearly i inch or even more in width Wild Leek 



bb Leaves linear 



c Flower cluster bulbiferous; capsule not 



crested Wild Garlic 



cc Flower cluster not bulbiferous; capsule 



crested Wild Onion 



aa Odor of Mint 



b Conspicuous whitish or purplish bracts below 

 the flower cluster 



c Heads of bloom terminal Wild Bergamot 



cc Heads of bloom axillary Horsemint 



bb No conspicuous bracts below flower cluster 

 c Flowers in terminal spikes 



d Leaves lance-shaped with toothed edges 

 (Fig. 3 /) 



e Leaves sessile or nearly so Spearmint 



ee Leaves petioled Peppermint 



dd Leaves heart-shaped with serrate edges 



(Fig. 3^) Catmint 



