pauciflorum) in a "mixed shrub" community on shale in northeastern Montana was attributed to 

 coarse textured substrate (loose platy material with high infiltration rates) weathered from shale with 

 low montmorillonite content (Branson et al. 1970). As with the Carter Co. representation of the 

 CALLON - CARINO type, the northeastern "mixed shrub" community), had the lowest values of 

 any community within its local matrix for a number of variables (total soluble cations, pH, 

 conductivity.) Calamovilfa longifolia is a deep-rooted, cool season grass that exploits deep soil 

 moisture, and becomes dominant on substrates with high infiltration rates and little runoff (Culwell 

 et al. 1986, Hanson and Hofftnan 1988). 



Comments: Near pristine vegetation sampled by Ross et al. (1973) on sandy loam soils in the Chalk 

 Buttes imit of the Custer National Forest in Carter County matches this type, except that the 

 indicated codominant sedge was Carex filifolia. A similar association with Carex filifolia was 

 observed elsewhere in the Carter County, though not documented. The habitat requirements and 

 plant association fidelities of Carex filifolia vs. C. inops ssp. heliophila require further investigation. 



Coupland (1961) hypothesizes that this type (or any site dominated by a suite of tall "sand" grasses, 

 e.g. Calamagrostis montanensis, Oryzopsis hymenoides, Elymus canadensis) to be autogenically 

 driven to the Stipa (comata) - Bouteloua (gracilis) - Agropyron (dasystachyum) faciation (a broadly 

 defined community type). However, we agree with Hansen and Hoffman (1988) that this is an 

 edaphic climax type, and that these sites possess a unique suite of soil descriptors. 



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