270 American Midland Naturalist Monograph No. 7 



1. Bracts of the involucre tipped with a rigid spine; plants annual. 

 8. Spines of the bracts 1-2.5 cm long. 



9. Flowers purple; stem wingless; heads sessile; waste places, 



occasional; adv. from Eur. June-Oct C. calcitrapa L. 



9. Flowers yellow; stem winged by the decurrent leaf-bases; 

 heads peduncled; waste places, occasional; adv. from Eur. 



July-Sept. Barnaby's Thistle C. solstitialis L. 



8. Bracts pectinate, the spine weak, 1-2 mm long; flowers whitish 

 or pink; stems angular; heads peduncled, numerous; road- 

 sides and waste places, occasional; native of Eurasia. July- 

 Sept C. diffusa Lam. 



58. Cnicus L. 



C. bencdictus L. Escaped from gardens; introd. from s. Eur. 



Tribe 12. Cichorieae 



59. Lapsana L. 



L. communis L. Nipplewort. Occasional weed along roads and 

 in waste places; nat. from Eur. June-Sept. 



60. Serinia Raf. 



S. oppositijolia (Raf.) Ktze. Moist sandy soil, s. 111. Mar. -Apr. 



61. Krigia Schreb. 



1. Plants perennial; pappus of 10-15 minute scales, and 15-20 long 

 bristles. 

 2. Plants with a solitaiy head on a leafless scape; involucre 10-15 

 mm high; plant bearing a .small globose tuber; open woods 

 in the southern half of 111. Apr. -May ....K. dandelion (L.) Nutt. 

 2. Plants with 1-3 clasping stem-leaves, and several heads; in- 

 volucre 8-10 mm high; plant without a tuber; wooded slopes 

 and ridges. May-Sept. [A', amplexicaulis (Miclix.) Nutt.] 

 '. K. biftora (Walt.) Blake 



62. Cichoriuni L. — Chicory 



C. intybus L. Roadsides and fields, common; nat. from Eur. Jime- 

 Nov. There are occasional white-flowered ])lants. 



63. Hypochaeris L. 



H . radical a L. Waste groimd, rare. Champaign Co., M. L. Briggs 

 in 1950. 



64. Picris L. 



1. Outer bracts of the involucre large, ovate, bristly-ciliate; achenes 



long-beaked; adv. from Eur.; reported from Hancock Co 



..P. echioides L. 



1. Outer bracts of the involucre linear-lanceolate, strigose; achenes 



short-beaked; adv. from Eur.; reported from Menard Co 



P. hieracioides L. 



