irregular with numerous fine marginal spines to 5 

 mm long; heads 3 cm high, 2.5 cm wide, arrangement 

 variable, usually in a close terminal cluster but 

 also 1-2 on stem apex and lateral branches, many 

 floriferous branches to 15 cm long, on terminal 

 third of main stem; floriferous part of stem may 

 be unexpanded in young plants with less than or 

 equal to 5 heads grouped at the stem apex; heads 

 subtended by a few reduced leaves, the uppermost 

 about the size of the involucral bracts and 

 approaching them in form, with gray multicellular 

 hairs at right angles to the margin; involucre 2 

 cm high with 5-6 rows of bracts, outer bracts 

 linear-lanceolate, base 1.5-2 mm wide, weakly 

 glandular or with a dark blotch, surface glabrous, 

 apical portion slightly dilated with a yellow 

 lacerate fringe, tipped by a slender 2 mm spine; 

 middle bracts similar but progressively less 

 dilated-lacerate; inner bracts longer, lanceolate, 

 tip not or only slightly lacerate, the lacerate 

 margin varies from a conspicuous yellow fringe to 

 minute irregular serrations and is best seen on 

 young heads but never consists of fine lateral 

 spines; flowers white, corolla 20-22 mm long, tube 

 7-9 mm, lobes 3.5-5.5 mm, pappus 18-19 mm, tawny, 

 of 30-40 setae, longer setae clavellate; anthers, 

 including appendages, 7.5-8.5 mm long, free tips 

 usually incurved; style long-exserted to 1 cm 

 beyond the corolla, tip to joint of style 3.5-5 

 mm; achenes 5.5-6.5 mm long, 2 mm wide, light 

 brown sometimes with purplish flecks (Schassberger 

 1991) . 



3. LOCAL FIELD CHARACTERS: Cirsium lonqistylum is 



distinguished from other species in the field by 

 its dilated, lacerate-fringed tips on the outer 

 involucral bracts, although this character is 

 somewhat variable. However this character 

 separates it from C. hookerianum (with long- 

 tapering, arachnoid-villose involucral bracts) and 

 C. scariosum (with occasional inner involucral 

 bracts dilated and fringed at the tip) . 



D. GEOGRAPHICAL DISTRIBUTION 



1. RANGE: Cirsium lonqistylum is known from 31 



locations in seven counties (Broadwater, Cascade, 

 Jefferson, Judith Basin, Lewis & Clark, Meagher, 

 and Wheatland) in central Montana in the Little 

 Belt, Big Belt, Castle, and Elkhorn Mountains. It 

 is endemic to Montana. Three of the new records on 

 the Helena Nation 



27 



