SPECIES INFORMATION 

 A. CLASSIFICATION 



1. SCIENTIFIC NAME: Cirsium lonqistvlum Moore & 



Frankton. 



2. COMMON NAME: long-styled thistle. 



3. FAMILY: Asteraceae (= Compositae, Sunflower Family) . 



4. GENUS: The genus Cirsium occurs throughout the 

 northern hemisphere and contains about 200 species, 

 about 50 of which are native to North America 

 (Cronquist 1955) . Eleven native species occur in 



Montana along with two introduced (non-native) species 

 from Eurasia (Dorn 1984) . 



5. SPECIES: Cirsium longistylum is endemic to central 

 Montana and is currently known primarily from the 

 Little Belt Mountains, with a single occurrence to the 

 west in the Big Belt Mountains. The type specimen 



( Senn. Frankton & Gillett (5666 ) was collected in 1951, 

 three miles southeast of Monarch, and is deposited at 

 the Department of Agriculture, Ottawa (DAO) . The 

 earliest known specimen was collected in 1896 in the 

 Little Belt Mountains (Moore and Frankton 1963) . A 

 chromosome number of 2n=34 has been reported for the 

 type collection and all others determined (Mathews 

 1990, Moore and Frankton 1963). 



Variation of some local populations in both leaf and 

 involucral characters has been interpreted to indicate 

 hybridization between C. lonqistvlum and perhaps C. 

 hooker ianum , which has been reported from the area 

 (Gorman 1987, Ownbey 1987, Shelly 1986). Similarities 

 to C. scariosum have also been noted (Moore and 

 Frankton 1963) . The incidence of these variant plants 

 seems to be greater in disturbed sites than in 

 undisturbed sites (Shelly 1986,), which is a common 

 pattern in many cases of hybridization (Anderson 1953). 

 More recently, Ownbey (1990) has stated that he thinks 

 the variation "can be ascribed to intraspecif ic genetic 

 variation" rather than hybridization. There is also 

 some question about the identity of the plants from the 

 area that were reported as C. hookerianum (Cronquist 

 1991) . Thus, there are currently unresolved questions 

 about the status of this species and further study is 

 needed. 



B. PRESENT LEGAL OR OTHER FORMAL STATUS 



