COMPOS1TAE (THISTLE FAMILY) 



14 a Only the lower leaves pinnately divided 15 



b All leaves more or less pinnately divided 16 



15 a Plants cultivated; leaves lanceolate to oblanceolate 



28. Gaillardia. p 234. 

 'b Plants wild; leaves ovate to triangular 



30. Polymnia. p 234 



16 a Heads erect or pendulous, not arranged in a corymb 



53. Artemisia, p 238 

 b Heads erect, arranged in a corymb; flowers yellow.. 17 



17 a Plant aromatic 52. Tanacetum. p 237 



b Plants not aromatic 58. Senecio. p 238 



18 a Flowers pink or purple, the heads in a dense raceme; 



leaves all basal, round-heart-shaped, appearing with 



or after the flowers 55. Petasites. p 238 



b Plants not completely as in a 19 



19 a All leaves entire or some with wavy margins 20 



b Some or all of leaves toothed or incised 27 



20 a Plants not woolly ; flowers not whitish 21 



b Plants more or less white-woolly 23 



21 a Heads in spikes or spike-like racemes; bracts of in- 



volucre in 4-6 rows 7. Lacinaria. p 227 



b Heads not in spikes or spike-like racemes 22 



22 a Bracts of involucre in several rows, usually not green 



16. Helichrysum. P 233 

 b Bracts of involucre in i or 2 rows, green 



15. Erigeron. p 233 



23 a Basal leaves present, broader than the stem leaves 



23. Antennaria. p 233 

 b No conspicuous basal leaves present 24 



24 a Bracts of involucre pearly-white, numerous, spreading 



24. A nap halts, p 234 

 b Bracts of involucre not pearly-white and spreading.... 25 



25 a Cultivated herb; heads usually solitary; bracts of in- 



volucre variously colored.... 26. Xeranthemum. P 234 

 b Wild herbs ; heads 2-30 in a cluster 26 



26 a Heads 12-30 in a cluster; bracts of involucre light 



yellow 21. Gifola. p 233 



b Heads 2-10 in a cluster; bracts of involucre not yellow 



25. Gnaphalium. p 234 



27 a Shrub with obovate leaves 1-3 in. long 



20. Baccharis. p 233 

 b Herbs 28 



28 a Some or all of leaves opposite or in whorls, few or none 



alternate 29 



b All of leaves alternate 33 



29 a Flowers white, pink, purple, or blue 30 



b Flowers not colored as in a 32 



222 



