38 



ASTERACEAE 



Helichrysum — Everlasting 

 (Gr. helios, sun, chrysos, gold, referring to the golden heads of some varieties) 

 Leaves lance-oblong, entire; scales papery, yellow, white or pink //. brae tedium 



Eupatorium — Eupatorium 



(Gr. eupatorion, a kind of medicinal plant) 

 1. Leaves petioled 



a. Leaves in whorls of 3-6 



(1) Leaves hairy and wrinkled 



(2) Leaves smooth 



b. Leaves opposite 

 2. Leaves sessile, opposite as a rule 



a. Leaves narrowed at base 



b. Leaves clasping, perfoliate 



/:'. maculdtum 



E. purpurcum : Joe-pye 



weed 

 E. agcraloides: sanicle 



E. altlssimum 



E. perjolidtum: boneset 



Kuhnia — Kuhnia 



(Named for Dr. Kuhn, a botanical collector of the ISth century) 



Leaves lanceolate ; heads cream-colored 



Yernonia — Ironweed 



(Named for Vernon, an English botanist) 



1. Bracts with long spreading awns 



2. Bracts merely acute 



Ageratum — Ageratum 



(Gr. ageraton, everlasting) 

 Leaves ovate or cordate ; flowers blue, rarely white 



A', eupaiorioides 



V. nozeboracensis 

 V . jascieuldta 



A, mcxicdna 



Xanthium — Cocklebur 



(Gr. name of a plant yielding a yellow^ dye; xanthos, yellow) 

 Leaves ovate; involucre with hooked spines X. canadense 



Iva — Marsh Elder 



(Of doubtful meaning) 

 Leaves ovate, white below; involucre smooth 



/. xanthijolia 



Tanacetum — Tan s y 



(From tansy, everlasting, from Gr. athanasia, immortality) 



Leaves twice pinnatifid, strong-scented ; flowers greenish yellow 



Artemisia — Wormwood 



(From Artemisia, wife of Mausolus) 



1. Leaves entire or lobed at tip 



a. Leaves glabrous, linear 



b. Leaves densely hairy or woolly 



(1) Leaves linear 



(2) Leaves oblong to lanceolate 



2. Leaves divided 



a. Heads erect 



(1) Leaves typically hairy; perennial 



(2) Leaves glabrous; annual or biennial 



b. Heads drooping 



( 1 ) Leaves silvery 



(a) Leaf segments linear 



(b) Leaf segments broad, ovoid 



(2) Leaves green 



Ambrosia — Ragweed. Kindiead 



1. Leaves palmately divided; tall 



(Gr. name of a plant) 



'/'. vulgire 



A. dracumuloides 



A. glauca 



A. gnaphalodes 



A. canadensis 

 A. biennis 



A. jrigida 

 A. absinthium 

 A. abrotanum 



A. Irifida 



