COMPOSITAE (COMPOSITE FAMILY) 587 



(mientose beneath, green, loosely tomentose, or glabrate above; the lower 

 12-17 cm. long, the lobes lanceolate to oblong, acute, prickly tipped and 

 margined: heads few, 4-5 cm. high and broad; outer bracts of the involucre 

 lanceolate to ovate-lanceolate, firm, dark, tipped with short, weak, spreading 

 prickles; the inner linear-lanceolate, unarmed, tipped with scarious, reflexed, 

 crose appendages: pappus of outer flowers merely barbellate. Sandy soil; 

 Nebraska to Wyoming and Montana. 



12. Carduus undulatus Nutt. Gen. 2: 130. 1818. Persistently white- 

 tomentose, 3-10 dm. high: leaves lanceolate or oblong-lanceolate, sessile or 



decurrent, or the lowest petioled, undulate, lobed or pinnatifid; the lobes 

 dentate, triangular, often very prickly: heads 3-4 cm. broad, nearly as high, 

 solitary at the ends of the branches; principal bracts of the involucre mostly 

 thickened on the back by the broad glandular-viscid ridge, comparatively 

 narrow, tipped with short, spreading prickles: corollas rose-color or pale purple 

 to white, with lobes equaling or longer than their throats. (C. nebraskensis 

 Brit, in Brit. & Brown Fl. 3: 487. 1898; C. floccosus Rydb. Bull. Torr. Bot. 

 Club 32: 133. 1905.) Dry plains of our range and extending both east- 

 ward and westward north of our range. 



12a. Carduus undulatus canescens (Nutt.) Porter, Mem. Torr. Club 5: 345. 

 1894. Apparently a perennial form from rhizomes or thickened roots: heads 

 mostly smaller, and the leaves varying from deeply pinnatifid to subentire. 

 (Cirsium canescens Nutt.; Cnicus undulatus canescens Gray.) Same range as 

 the species, but infrequent. 



13. Carduus megacephalus (Gray) A. Nels. Stems low, 3-5 dm. high, 

 simple or branched, the stem or branches each bearing one large pedunculate 

 head 6-8 cm. high and broad: leaves rather broadly lanceolate, more or less 

 deeply laciniate-toothed, each tooth tapering into the stout, yellowish spine: 

 otherwise like C. undulatus. (Cnicus undulatus megacephalus Gray, Proc. 

 Am. Acad. 10: 42. 1874.) Nebraska and Wyoming to Kansas, New Mexico, 

 and Texas. 



14. Carduus ochrocentrus (Gray) Greene, 1. c. Similar to Carduus un- 

 dulatus, but commonly taller and more leafy, often 2 m. high, equally white- 

 tomentose: leaves oblong-lanceolate in outline, usually very deeply pinnatifid 

 into triangular-lanceolate, serrate or entire segments, armed with numerous 

 long yellow prickles; lower leaves often 15-30 cm. long: heads about 5 cm. 

 broad, 4-5 cm. high, solitary at the ends of the branches; outer bracts of the 

 involucre lanceolate, tipped with stout yellow prickles of nearly or quite their 

 own length; the inner narrowly lanceolate, long-acuminate: flowers purple. 

 Dry plains; Nebraska to Nevada and Texas. 



15. Carduus filipendulus (Engelm.) Rydb. 1. c. 33: 157. 1906. Stem 

 comparatively slender, 5-10 dm. high, somewhat angled and striate, more 

 or less covered with a cottony pubescence: leaves more or less floccose, but 

 green above, densely white-tomentose beneath, deeply divided into linear- 

 oblong or lanceolate acute lobes tipped with rather weak, yellowish spines: 

 heads campanulate or sometimes nearly cylindric; bracts imbricated, the 

 outer much shorter, ovate, the inner lanceolate, all more or less floccose on 

 the margins, especially when young, and with a narrow glandular ridge, all 

 but the innermost tipped with a weak, erect or slightly spreading spine: 

 corolla rose or reddish-purple: achenes striate; pappus plumose. (C. Flod- 

 manii Rydb. Mem. N. Y. Bot. Card. 451. 1900; C. oblanceolatus Rydb. Bull. 

 Torr. Bot. Club 28: 510. 1901.) Wyoming to New Mexico and eastward to 

 the Missouri. 



92. CICHORIUM L. CHICORY 



Erect herbs, the leaves mostly near the base, those of the stiff branching 

 stem reduced and bract-like. Receptacle without bracts. Bracts of the ob- 

 long involucre herbaceous, in 2 series; the outer somewhat spreading; the 

 inner erect, the lower part half infolding the marginal achenes. Achenes 

 5-angled, truncate, beakless. Pappus of 1-3 series of short blunt scales. 



