~* 116 



25a. Achene tipped with a slender beak, bearing the pappus at its 



summit (summer) (Wild Lettuce) 26. 

 25b. Achene without a beak 29. 



26a. Leaves hirsute or hispid on the mid-veins beneath 27. 

 26b. Leaves glabrous 28. 



27a. Leaves pubescent on both sides (1 2 m. high) 



Wild Lettuce, Lactuca hirsuta. 

 27b. Leaves glabrous, except on the mid-vein (5 15 dm. high) 



Wild Lettuce, Lactuea scariola var. integrata, 

 28a. Leaves entire or sparsely toothed (1 2 m. high) 



Wild Lettuce, Lactuea sag-ittifolia. 

 28b. Leaves chiefly sinuate-pinnatifid (13 m. high) 



Wild Lettuce, Lactuce canadensis. 



29a. Flowers white, cream-color, or purplish (summer and autumn) 



(Rattlesnake Root) 30. 

 29b. Flowers bright-yellow or orange 33. 



30a. Heads nodding (620 dm. high) 31. 



30b. Heads pointing in various directions, in spike-like panicles; 

 involucres pubescent (5 15 dm. high) 



Rattlesnake Root, Prenanthes racemosus. 

 31a. Heads with 5 7 flowers in each 



Rattlesnake Root, Prenanthes altissima, 

 31b. Heads with 812 flowers 32. 

 31c. Heads with 20 or more flowers 



Rattlesnake Root, Prenanthes crepidinea. 

 32a. Pappus dark reddish-brown 



Rattlesnake Root, Prenanthes alba. 

 32b. Pappus pale-brown or nearly white 



Rattlesnake Root, Prenanthes trifoliata. 



33a. Pappus tawny or brown in color (summer and autumn) (Hawk- 

 weed) 34. 

 33b. Pappus white 42. 



34a. Heads 2.5 cm. in diameter, or larger 35. 



34b. Heads 1 2 cm. in diameter (4 10 dm. high) 37. 



35a. Leaves all basal (1 4 dm. high) 



Hawkweed, Hieracium pilosella, 



35b. Stem-leaves present (4 15 dm. high) 36. 



36a. Leaves rounded at the sessile base 



Hawkweed, Hieracium canadense. 

 36b. Leaves narrowed toward the base 



Hawkweed, Hieracium umbellatum. 



37a. A rosette of basal leaves conspicuous at flowering time 38. 

 37b. No rosette of basal leaves at time of flowering 41. 



38a. Leaves glabrous on the upper side 39. 

 38b. Leaves hairy on the upper side 40. 



