KEY FOR JUNE TO NOVEMBER 



245 a Leaves usually less than i in. long 246 



b Leaves usually i in. or more long 247 



246 a Flowers in panicles Lechea. p 186 



b Flowers in axillary and terminal spikes or clusters 



Amaranthus. p 148 



247 a Flowers solitary in the axils; leaves sessile. Ludivigia. p 189 

 b Flowers not solitary in the axils ; leaves petioled 248 



248 a Mealy or scurfy plants; some leaves usually triangular 



A triplex, p 14.8 

 b Plants not mealy or scurfy; leaves ovate to lanceolate.. 249 



249 a Leaves rather ovate; plants not growing in saline 



places Amaranthus. p 148 



b Leaves lanceolate; plant growing in saline places 



Acnida. p 148 



250 a Pistils 5 to each flower, very distinct; flowers in re- 



curved cymes Penthorum. p 161 



b Flowers not completely as in a 251 



251 a Plants with a rosette of basal leaves 252 



b Plants not with a rosette of basal leaves 253 



252 a Leaves lobed only at the base. . . .Rumex acetosella. p 145 

 b Leaves lobed or pinnatifid throughout Lepidium. p 757 



253 a Flowers in the axils of the leaves and subtended by a 



palmately-lobed bract Acalypha. p 180 



b Flowers not subtended by a bract as in a 254 



254 a Pistillate flowers enclosed in a spiny involucre' 



Xanthium. p 221 

 b Pistillate flowers not enclosed in a spiny involucre .... 255 



255 a Several small flowers collected into heads which are 



subtended by an involucre of bracts ; heads of flowers 



stalked 256 



b Flowers not completely as in a 259 



256 a Flowers all with a distinct, irregular corolla.. Nabulus. p 220 

 b Flowers all regular or not completely as in a 257 



257 a Leaves merely toothed or sometimes incised, not pinna- 



tifid Erechtites. p 238 



b Leaves pinnately divided or lobed 258 



258 a Involucre of a few rows of separate bracts 



Artemisia, p 238 

 b Involucre of united bracts so as to appear tubular 



Ambrosia, p 220 



259 a Most of the leaves toothed or slightly lobed 



Chenopodium. p 147 

 b Leaves usually triangular with spreading, basal lobes 



Atriplex. p 148 



43 



