COMPOS1TAE (THISTLE FAMILY) 



39 a All leaves entire, rough 



DENSELY-FLOWERED ASTER. (A. multiflbrus.) 

 b Some of the leaves usually toothed, not rough 40 



40 a Lower leaves oblanceolate to linear-lanceolate, usually 



petioled, long-pointed at apex 



HAIRY-STEMMED ASTER. (A. hirsuticdulis.) 

 b Lower leaves linear to lanceolate, sessile, pointed at apex 



TRADESCANT'S ASTER. (A. trades cdnti.) 



41 a Lower leaves ovate to lanceolate, usually petioled 



STARVED ASTER. (A. lateriftbrus.) 

 b Lower leaves linear to lanceolate, sessile 42 



42 a Branches nearly horizontal ; lower leaves entire or some- 



times toothed SMALL WHITE ASTER. (A. vimineus.) 



b Branches ascending; lower leaves toothed 



TRADESCANT'S ASTER. (A. tradescdnti.) 



15 ERfGERON. 



1 a Heads 1-2 in. broad; stem not usually branched above 



ROBIN'S PLANTAIN. (E. pulchellus.) 

 b Heads usually %-x in. broad; stems usually branched 



above 2 



2 a Ray flowers rose-purple, 100 or more to a head 



PHILADELPHIA FLEABANE. (E. philadelphicus.) 

 b Ray flowers white or purple tinged, 70 or less to a head 3 



3 a Stem leaves toothed SWEET SCABIOUS. (E. dnnuus.) 



b Stem leaves entire DAISY FLEABANE. (E. rambsus.) 



16 HELICHR^SUM GOLDEN IMMORTELLE. (H. bractedtum*) 



17 LEPTILON HORSE-WEED. (L. canadense.) 



1 8 DOELLINGfeRIA. 



i a Heads comparatively numerous ; leaves lanceolate to 



oblong FLAT-TOPPED WHITE ASTER. (D. umbelldta.) 



b Heads comparatively few ; leaves obovate to oblong- 

 lanceolate CORNEL-LEAVED ASTER. (D. infirma.) 



19 IONACTIS STIFF ASTER. (I. linariifblius.) 



20 BACCHARIS GROUNDSEL TREE. (B. halimifblia.) 



21 GIFOLA CUDWEED. (G. germdnica.) 



22 PLUCHEA SALT-MARSH FLEABANE. (P. camphordta.) 



23 ANTENNARIA. 



1 a Basal leaves %-% in. broad, distinctly i-nerved 2 



b Basal leaves Mj-2 in. broad, distinctly 3-5-nerved. ... 4 



2 a Mature basal leaves i in. or less long, obovate ; stolons 



leafy throughout SMALLER CAT J S-FOOT. (A. neodiolca.) 



b Mature basal leaves usually more than i in. long, ob- 

 lanceolate 3 



3 a Stolons leafy throughout; basal leaves 1-2 in. long 



CANADIAN CAT'S-FOOT. (A. canadensis.) 

 b Stolons leafy only toward the tip; basal leaves 1-3 



in. long FIELD CAT'S-FOOT. (A. neglecta.) 



233 



