HABITAT: The Long Pines population of Asclepias ovalifolia occurs on an alluvial terrace along a 

 small drainage on the Long Pines escarpment. It is near a forest opening among widely spaced trees 

 in a partially burned stand of ponderosa pine {Pinus ponder osa). The tree canopy cover is semi-open, 

 but there is a high undergrowth vegetation cover, dominated by Kentucky bluegrass {Poa pratensis), 

 western snowberry {Symphoricarpos occidentalis), and creeping Oregon grape {Mahonia repens). 

 The soils are derived from sandstone parent material, and are a dry, brown, sandy loam. The site is at 

 3740-3840 ft. 



Note: Most sandstone escarpment habitat in Carter County is on the Custer National Forest, but 

 small adjoining BLM parcels, and larger tracts of BLM land in southwestern Carter County (Belcher 

 Mountain area) may have habitat appropriate for Asclepias ovalifolia. 



SPECIES BIOLOGY: Ovalleaf milkweed spreads by rhizomes, perhaps enabling it to survive and 

 compete in the dense sod-forming grass and high shrub cover. This mode of vegetative reproduction 

 means that any count of flowering stems in a population does not represent actual numbers of 

 genetically discrete individuals and is likely to over-estimate the number of individuals. 



This species, like all species of milkweeds, is adapted to cross-pollination by insects in having 

 stigmatic glands that adhere it insect visitors, and pollen that adheres into masses (poUinia) for mass- 

 transport. Despite the abimdant flowering activity among the 400+ stems in the Long Pines 

 population in 1994, only one plant was observed with fiTiit at the end of the growing season (Heidel 

 and Dueholm 1995). This may reflect a paucity of pollinators, or else other late-season conditions 

 that would have interfered with fruit set and development. 



OTHER COMMENTS: The Long Pines population of ovalleaf milkweed is located in part of an 

 active allotment that is in good range condition. The primary sign of habitat alteration that may be 

 associated with livestock use is invasion by Kentucky bluegrass {Poa pratensis). Livestock usually 

 avoid milkweeds {Asclepias spp.) and find them unpalatable. However, the valleybottom habitat is 

 an area of concentrated use, and there is preliminary evidence at the Long Pines site to suggest that 

 trampling may be a detriment (Heidel and Dueholm 1995). 



This species evidently survived the Long Pines fire, which burned as an understory fire in the 

 species' habitat. The fact of its persistence means only that it survives fires under the particular 

 timing and intensity of that event, and it cannot be interpreted as a general response without 

 additional information. 



We have considered many but not all of the small, scattered BLM tracts adjoining Custer National 

 Forest that have sandstone outcrops. Therefore, while it is unlikely to be on BLM-administered land, 

 we have not ruled out the possibility and this survey does not provide a basis for changing its watch 

 status. 



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