20 



lobed corolla is white, v;ith a yellow throat, nearly " 

 regular, and 5-10 mm (.2-. 4 in) long, with the lobes equal 

 or a little less than the corolla tube. It has four anthers 

 and five distinct sepals; the outer sepal broad, rotund- 

 elliptic, the others much narrower (from Hitchcock and 

 Cronquist 1973, Larson 1993). 



2. TECHNICAL DESCRIPTION: Fibrous-rooted perennial; stems 

 succulent, branched, 1-4 dm (4-16 in) ; distally-f loating and 

 spreading-hairy ; leaves opposite, sessile, entire, palmately 

 several-nerved, broadly rotund-obovate to suborbicular , 1-3 

 cm (.4-1.2 in) long, glabrous; pedicels stout, 0.5-2 cm (.2- 

 .8 in) long; sepals 3-5 mm (.1-.2 in) long, the outer one 

 broad, rotund-elliptic, the others much narrower; corolla 

 white with yellow throat, narrowly-campanulate , 5-10 mm (.2- 

 ,4 in) long, the lobes equalling, or a little shorter than 

 the tube (Hitchcock et al . 1934). 



3. LOCAL FIELD CHARACTERS: The opposite, sessile, round, 

 palmately-veined leaves are distinctive among aquatic plants 

 in eastern Montana. 



GEOGRAPHICAL DISTRIBUTION 



1. RANGE: Round-leaved water-hyssop ranges from Indiana to 

 Idaho, and south to Mississippi and Texas; also in 

 California. All Montana records are from plains of central 

 Montana, including Garfield, Philips and Cascade counties. 



2. CURRENT SITES: Collections made in Garfield and Phillips 

 counties are recent and presumed extant. 



3. HISTORICAL SITES: The Cascade County collection was made 

 before the turn of the century near Great Falls (Lower Sand 

 Coulee) in an area that is extensively plowed and developed, 

 where it has been sought and is presumed extirpated. 



4. UNVERIFIED/UNDOCUMENTED REPORTS: None. 



5. AREAS SURVEYED BUT SPECIES NOT LOCATED: Watercourses 

 throughout the Fort Union and Hell Creek Formations were 

 searched for this species without success. It is possible 

 that these settings are too alkaline, in which case only the 

 few wetland pockets and spring-fed watercourses south of 

 Fort Peck Reservior represent potential habitat. Only a few 

 sites of the latter habitat were found, but not round-leaved 

 water-hyssop. 



