composite 335 



5, the anthers united around the 2 stylos: fruit dry and 1 -seeded, 

 indehiscent, usually crowned with a pappus which represents :i 

 calyx. The largest of all phenogamous families, comprising about 

 one-tenth of all flowering plants, about 800 genera and 11,001 

 12,000 species. Common composites are sunflower, aster, golden rod, 

 boneset, dahlia, chrysanthemum, marigold, compass plant, thisl 

 dandelion, lettuce. 



a. Head with all the flowers strap-shaped (with rays i and 

 perfect: juice milky: leaves alternate. 



b. Flowers yellow 1. 2 tin 



bb. Flower- blue or pink 2. < 'ichoi 



\\. Head with tubular and mostly perfect disk flowers, the 



rays, if any. formed of the Miter strap-shaped and 



imperfecl flowers. In cultivated species, all the 



(lowers may become strap-shaped i head "double " i : 



juice not milky. 



b. Fruit a completely closed and bur-like involucre, 



containing one or two small akenes : flowers 



imperfect. 



<. Involucre-bur large and sharp-spiny 3. Xanth 



i . Involucre ii\ ii- small, not sharp-spiny I. Atnbro 



bb. Fruit not formed of a closed and hardened involucre 

 (although the involucre may be spiny, as in 

 Arctium and I Inicus I. 

 c. Pappus none. 



d. Leaves opposite, simple 5. Agerai 



dd. Leaves alternate. 



b. Poliage finely divided ,; - Achillea 



ee. Foliage entire, toothed or broad-lobed. 



f. Akenes curved or horseshoe shaped .... 7. Cah ud 

 pp. Akenes straight. 



q. Torus tl.it or slightly convex B.< 'hrysanthi 



GG. Torus conical 9. Rudbei 



. Pappus of _ thin early deciduous Bcales I"- Helianthut 



occ. Pappus a short crown 1 1 / 



CCOO. Pappus of many brisl Li 



i>. Plant very prickly 12. Cw 



dd. I'lant not prickly. 



E. I ii vol ue re prickly and bnr-like i i 



ii. I n\ olucre aot a bur nor prlcklj . 



i . Torus bristly (chaff or bracts amonl 



the Morels i II I 



II. TorUS naked. 



i;. Bays i re-, ni. 



ii. i lolor yellow, the bi ads \ erj small 



Mil. < lolOr DOt J ellow. 



i. Scales of in\ olucre unequal . ... 10 ' 



ii. Scales equal In lenjftb ' 



in. Scales i 



l. 

 ..... i;:, none 



