Stem glabrous, leafless or with one or two leaves 



Hawkweed, Hieracium venosum. 

 Stem with several leaves, hairy below 



Hawkweed, Hieracium marianum. 



40a. Leaves with short scattered hairs above 



Hawkweed, Hieracium gronovii. 



40b. Leaves and stem densely covered with very long hairs 



Hawkweed, Hieracium longipilum. 



Leaves glabrous Hawkweed, Hieracium paniculatum. 



Leaves very hairy Hawkweed, Hieracium scabrum. 



42a. Bracts of the involucre smooth (5 20 dm. tall; summer and 



autumn) (Sow Thistle) 43. 

 42b. Bracts of the involucre hairy 44. 



The clasping leaf-bases acute Sow Thistle, Sonchus oleraceus. 



The clasping leaf-bases rounded Sow Thistle, Sonchus asper. 



44a. Heads 2.5 5 cm. broad; involucre 2 cm. long (4 10 dm. 



high) Sow Thistle, Sonchus arvensis. 



44b. Heads 1 '2 cm. broad; involucre 6 10 mm. long (3 6 dm. 



high; summer) Hawksbeard, Crepis tectorum. 



Leaves or involucre or both spiny (thistles, burdock, etc.) 46. 



Neither leaves nor involucre spiny 60. 



46a. Leaves 1 4 dm. broad, not spiny (flowers purple or white; 



summer) (Burdock) 47. 

 46b. Leaves narrower, not spiny 48. 

 Diameter of involucre at flowering time 3 5 cm. (1 3 m. high) 



Burdock, Arctium lappa. 



Diameter of involucre at flowering time 1.5 3 cm. (5 15 dm. 

 high) Burdock, Arctium minus. 



48a. Each head 1-flowered; heads aggregated in a globular head- 

 like cluster (1 2 m. high; flowers blue or white, -summer) 



Globe Thistle, Echinops sphaerocephalus. 

 48b. Each head many-flowered 49. 



Principal involucral bracts with stout spreading spines 2 4 cm. 

 long (5 15 dm. high; flowers purple, summer) 



Milk Thistle, Silybum marianum 



Principal involucral bracts with slender spines or none 50. 

 50a. Pappus feathery; receptacle bristly (summer and autumn) 



(Thistle) 51. 



50b. Pappus not feathery (flowers purple, summer) 59. 

 Heads subtended by a circle of large leafy bracts (5 15 dm. 

 high; flowers pale-yellow) Thistle, Cisium spinoissimum. 



Heads not subtended by several leafy bracts 52. 

 52a. Leaves conspicuously white-woolly on both sides (4 10 



dm. high) 53. 

 52b. Leaves conspicuously white-woolly or brown-woolly below, 



not above (flowers purple or pink) 54. 



52c. Leaves green on both sides (flowers pink or purple, rarely 

 white) 56. 



