542 Rydberg : Rocky Mountain flora 



species. It seems as if it should be unnecessary to propose more, 

 but it has been impossible for me to include the following four 

 in any known species. 



Carduus polyphyllus sp. nov. 

 Carduus scopulorum Rydb. Mem. N. Y. Bot. Gard. 1: 449. 1900. 



Not C. scopulorum Greene. 1892. 



Perennial; stem stout, 3-8 dm. high, very leafy, angled, arach- 

 noid-hairy; leaves 1-2 dm. long, linear in outline, deeply pinnati- 

 fid, with lanceolate divisions ending in yellow spreading spines, 

 green on both sides, sparingly arachnoid-hairy; heads hemis- 

 pheric, about 3 cm. high and broad, usually numerous, sessile 

 in the axils of the leaves, often forming a leafy spike 2-3 dm. long; 

 bracts linear-subulate, densely arachnoid-hairy, the outer with 

 rather long yellow spines often 1 cm. long, the inner attenuate 

 into slender straight tips; corollas straw-colored; pappus plumose 

 with slender, barbellate tips. 



In my Flora of Montana, I referred this species to Carduus 

 scopulorum Greene. The latter was based on Cnicus eriocephalus 

 or Cirsium eriocephalum A. Gray, the type of which was collected 

 by Parry in Colorado. The rather common Colorado plant is 

 characterized by its leaves, which are grayish-tomentose beneath, 

 and by its heads conglomerate at the end of the stem, forming a 

 cluster which at first is nodding. Carduus polyphyllus is more 

 closely related to C. Kelseyi and C. Tweedyi. From the latter it 

 differs in the straw-colored instead of red corollas, the narrower 

 bracts, and more numerous leaf -lobes, and from the former in 

 the deeply dissected and decidedly crisp leaves. If the leaves are 

 lobed at all in C. Kelseyi the spines are directed forward and the 

 blades are almost perfectly flat. 



Montana: Mountains near Indian Creek, July 21, 1897, 

 Rydberg & Bessey '5216 (type, in herb. N. Y. Bot. Gard.) ; Park 

 Co., Aug., 1887, Tweedy 349. 



Carduus Butleri sp. nov. 



Perennial or biennial; stem angled, striate, purple, sparingly 

 arachnoid-hairy, very leafy, 6-10 dm. high or more; leaves linear- 

 oblanceolate or linear, almost entire or sinuately lobed, spinulose- 

 ciliate and if lobed the short lobes ending in slightly stronger 

 spines, green and sparingly arachnoid above, grayish-tomentose 



