Both of these other species require moisture ii^ levels 

 above that supplied through precipitation alone or by 

 compensating environments where evaporative losses 

 are mitigated. 



The Prunus wVginiana-dominated community has an 

 undergrowth with Stipa comata dominant but with 

 Pascopyrum smithii prominent whereas the 

 Symphoricarpos ocddentafa -dominated communities 

 have an undergrowth with the abundances of these 

 undergrowth species switched (Stipa comata relegated 

 to merely present in most cases) . It would be difficult 

 to envision a scenario wherein the Pascopyrum. smithii 

 was grazed out of the ELECOM / STICOM p.a. and 

 not the adjacent P. virginiarui- and S. occidentalis- 

 dominated communiities. In keeping with the sandy 

 substrate, by far the dominant forb in ELYCOM / 

 STICOM was slimleaf scurfpea {Psoralea lanceolata) ; 

 other forbs were present in only trace amounts. 

 Wildlife browsing has been intensive on the Elaeagnus 

 with shrubs attaining only 3-3.5 ft. height in 11 to 12 

 years. [Plot NHMTECRA97SC00031 



lanceolata Sparse Vegetation) . The unconsolidated 

 sand substrate constitutes over 90 % of the cover at the 

 surface, and the vegetation canopy cover is less than 5 

 %. This is a fundamentally different vegetation than 

 the Centennial sandhills, but these two sites have one 

 rare plant species in common (Cryptantha fendleri) as 

 well as analogous successional processes (Lesica and 

 Cooper 1999). 



SPECIES: 



Four Montana pant secies of special concern have been 

 documented in the Medicine Lake Wilderness Area; 

 two in the course of this study. Species site information 

 is presented on the Element Occurrence Records in 

 Appendix E, and annotated illustrations are in 

 Appendix F. Detailed information is lacking to 

 compare their numbers in the Refuge to elsewhere on 

 the Sandhills for providing concise statements of 

 botanical significance. Nonetheless, for its habitat 

 uniqueness and accrued botanical information, it 

 represents the highest known concentration of rare 

 plants in the Sandhills and in the county. 



In general, Elaeagnus commutata is rarely regarded as a 

 shrubland dominant in the south of the 49* Parallel 

 except possibly as a localized feature on limestone, 

 including montane settings, or on well-drained 

 Northern Great Plains grasslands in idle conditions and 

 with ample moisture. 



Prunus virginiana Shrubland 



[PRUVIR] 



common chokecherry shrubland 



Common chokecherry (Prunus virginiana) dominates 

 very small stands within the Sandhills; the stems had 

 been exceedingly hedged by wildlife browsing and the 

 leaves fed on by insects. The undergrowth has both 

 needle-and-thread (Stipa comata) and western 

 wheatgrass (Pascop^irum smithii) as dominants, their 

 roles apparently shifting by site. This type is found 

 primarily on the undulating flats but also occurs on 

 slopes of arrested dunes, sites seemingly too dry for a 

 species normally associated with mesic sites. [No Plot) 



Oryzopsis hymenoides / Psoralea lanceolata Sparse 



Vegetation 



[ORYHYM/PSOLAN] 



indian ricegrass / lemon scurf-pea barrens 



A recent blowout early in the process of stabilization 

 was sampled that represents an indian ricegrass / lemon 

 scurf-pea barrens (Oryzopsis hymenoides I Psoralea 



Fendler's cat's-eye (Cryptant/ua fendleri) occurs in the 

 Sandhills on discrete zones of unstable sand, often the 

 leeward rim of active dune blowouts. It was found in 

 two of the most active blowouts on the Refuge, perhaps 

 a small segment of a much larger population complex 

 alluded to by Lesica in estimating total plant numbers 

 in excess of 10,000 across the entire Medicine Lake 

 Sandhills. 



Schweinitz' flatsedge (Cyperus schweinitzii) also occurs 

 on unstable sand, often in the hollow at the head of an 

 active blowout. It was found at a single site on the 

 Refuge, presumable part of a much larger population 

 complex alluded to by Lesica in estimating total plant 

 numbers as "many thousands" across the entire 

 Medicine Lake Sandhills. 



Hairy four o'clock (MirabiUs hirsuta) is widely scattered 

 in low numbers across a range of sandy habitats. It 

 shows no discernible habitat specificity in relation to 

 composition or structure. It is present in both the 

 Medicine Lake Sandhills and Big Island. It has since 

 been documented outside of the Refuge in disturbed 

 settings including roadsides and CRP. It exhibits the 

 distribution pattern of an adventive species, thus 

 providing the basis for removing it from the list of 

 Montana plant species of special concern to the watch 

 list. Yet it is only known from three counties and seven 

 collection records so that field data will continue to be 

 compiled on it for further evaluation. 



48 



