KEY FOR JUNE TO NOVEMBER 



22$ a Several small flowers collected into a dense head and 

 subtended by an involucre of bracts ; ovaries crowned 



by barbed bristles Bidens. p 236 



b Flowers not completely as in a 229 



229 a Leaves with lobed or dissected margins . . . .Ambrosia, p 220 

 b Leaves with entire or toothed margins 230 



230 a Leaves with entire margins 231 



b Some or all of leaves with toothed margins 234 



231 a Stem 4-sided; flowers about }4 in. long Rotala. P 189 



b Stems rounded 232 



232 a Plants hairy; flowers in panicles Lechea. p 186 



b Plants not hairy; flowers not usually in panicles 233 



233 a Flowers in cymes; leaves % in. or less long. .Anychia. p 151 

 b Flowers in spikes or axillary clusters; leaves usually i 



in. or more long A triplex, p 148 



234 a Perianth irregular and distinct 235 



b Perianth regular or indistinct 236 



235 a Flowers clustered in whorls which are arranged in 



spikes Agastache. p 206 



b Flowers not clustered as in a Scrophularia. p 210 



236 a Some of the upper leaves with entire margins; leaves 



often somewhat triangular A triplex, p 14.8 



b All leaves with toothed margins 237 



237 a Petioles usually longer than the leaf blade; flower 



clusters shorter than the petioles Adicea. p 145 



b Petioles usually shorter than the leaf blade; flower 



clusters often longer than the petioles. .Boehmeria. P 145 



238 a Plants covered with whitish, woolly hairs 239 



b Plants not covered with whitish, woolly hairs 240 



239 a Some or all of leaves pinnately divided or dissected 



Artemisia, 

 b Leaves with entire margins Gifola. p 233 



240 a Climbing or trailing vine with the leaves rounded, 



more or less lobed or angled Menispermum. p 154. 



b Plants not completely as in a 241 



241 a Leaves with entire or wavy margins 242 



b Leaves with toothed, lobed, or dissected margins 250 



242 a Flowers distinctly irregular, about ^4 in. long 



Cubelium. p 188 

 b Flowers not distinctly irregular 243 



243 a Plants with a membranous sheath around the stem at 



the base of the petiole 244 



b Plants not completely as in a 245 



244 a Perianth 6-parted ; fruit with 3 wing-like structures 



Rumex. p 145 

 b Perianth s-parted Polygonum. p 146 



41 



