semipersistent. Ray florets absent. Outer peripheral florets pistillate and 

 fertile. Pistillate florets with a minute tubular corolla. The few infertile central 

 florets with a 4-toothed corolla, 4 very small anthers, and a non-functional 

 ovary. Achenes oblong-elliptic in outline, compressed, 0.6-0.9 mm long, 

 sharp-edged, yellowish-brown and somewhat translucent; pappus none 

 (Barkley 1986). 



3. LOCAL FIELD CHARACTERS: The distinguishing features of £vax 



prolifera are its small size, woolly appearance, and clustered heads. Close 

 examination reveals alternate leaves, no true involucre and no pappus. Several 

 other small woolly species could be confused with rabbit-tobacco, but can be 

 distinguished as follows: 



Filago arvensis is usually taller (though still small) with an unbranched stem. 

 Heads are single in leaf axils. The achenes have a pappus of capillaiy brisfles. 

 This species is known from southeast and western Montana (Dom 1984) and 

 northeast Wyoming (Dom 1992). 



Gnaphalium palustre has a true involucre and a pappus of capillary achenes. 

 Heads are not clustered. This species is known from northeast, central, and 

 western Montana (Dom 1984), occurs tliroughout Wyoming (Dom 1992), and 

 in the Black Hills and along the Missouri River in South Dakota (Van Bruggen 

 1985). 



Psilocarphus brevissimus is perhaps the most similar in appearance. Its leaves 

 are mostly opposite. The receptacular bracts are woolly and enclose the florets 

 (those of Evax prolifera are thin, pale, and glabrous). This species is known 

 from north-central Montana (Dom 1 984) and from northeast Wyoming (Dom 

 1992). 



C. GEOGRAPHICAL DISTRIBUTION 



1. GLOBAL RANGE: Southwestern South Dakota, western Nebraska, and 

 Kansas to eastem Colorado; Oklahoma to Texas and Arizona. This species is 

 not knovvTi from Wyoming; its discovery in Montana therefore represents a 

 major range extension. 



2. STATE DISTRIBUTION: Known from Powder River County on the 

 Ashland District and from an historic collection in the Fort Keogh Range 

 Experiment Station in Custer County, about. 50 miles farther north (Figure 20). 

 The latter was uncovered in checking the Rocky Mountain Herbarium for 

 other specimens. 



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