Note: Similar habitat occurs within the Long Pines in the 

 vicinity of Plum Creek, northwest of Camp Crook (in T.2.S- 

 R.62E.)/ only part of which has been searched. Further survey 

 of this area in June or early July would be appropriate in the 

 course of local resource evaluations and planning. 



3. Occurrence in the study area: The two Sioux District 

 populations of Asclepias ovalifolia are on Chalk Butte and the 

 Long Pines. Their habitat is so highly localized that they 

 are likely to be outlying populations for population centers 

 possibly outside the Forest which were not located. It is not 

 known from the South Dakota units of the District. 



Habitat 



1. Associated vegetation: In the Long Pines this species 

 occurs on slightly grazed mixed-grass prairie, with 

 approximately 70 percent bare ground and 20 percent graminoid 

 cover. Scattered Pinus ponderosa are present near the edge of 

 the grassland, mostly saplings. The grassland contains a 

 mixture of several graminoids including Carex pennsvlvanica , 

 Koeleria macrantha , Aristida fendleriana , Dichanthelium 

 wilcoxianum , and, near the margins of the grassland, 

 Andropogon scoparius . A few forbs, typical of sandy sites, 

 are present. They are Artemisia campestris , A. ludoviciana , 

 Eriogonum annuum , Helianthus rigidus, Heterotheca villosa , 

 Penstemon anqustif olius , and Psoralea argophvlla . 



In the Chalk Buttes, the habitat is exposed prairie on ridge 

 crests and butte top, dominated by Stipa comata, Carex 

 f ilifolia , Calamovilfa longifolia . Andropogon scoparius , and 

 Psoralea lanceolata . The areas are ungrazed. 



2. Topography: The Long Pines population occurs on the south 

 to southwest slope of a small hill in a valley bottom. The 

 slope is slightly moderate, app. 10 percent, and straight to 

 slightly convex. The elevation ranges from app. 1103 to 1110 

 m (3620 to 3640 ft) . 



3. Soil relationships: The soil at both population sites is 

 a fine brown sandy loam. A blowout occurs in very sandy soil 

 just below the Long Pines site. 



Population biology and biological interactions 



1. Population size and condition: The Long Pines population 

 consists of six plants, with multiple stems, within an area of 

 less than one acre. All plants appeared healthy in June and 

 early July, no plants were found in late August. No fruits 

 were ever observed, and it is likely that the plants dried out 

 during the late drought of July-August. 



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