10 MUSEUM BULLETIN NO. 26. 



As mentioned above, the vegetation of the southern part of the 

 third prairie steppe is decidedly xerophile. As a result, a number of 

 species occur which approach desert types in being, in some way or other, 

 protected against rapid transpiration. Such plants are: Eriogonum 

 flavum, Eurotia lanata, Opuntia polyacantha, Mamillaria vivipara, Potentilla 

 Hippiana, Oxytropis splendens, Linum rigidum, Plantago Purshii, Aplo- 

 pappus spinulosus, Artemisia frigida, A. cana, A. Ludoviciana, Senecio 

 canus, Iva axillaris, Lygodesmia juncea, and others. 



Of other plants, characteristic of the southern part of the third 

 prairie steppe, the following may be mentioned: Bouteloua oligostachya, 

 Munroa squarrosa, Schedonnardus paniculatus, Oryzopsis hymenoides, 

 Stipa spartea, S. comata, Sporobolus Richardsonii, Calamagrostis americana, 

 Danthonia intermedia, Agropyron dasystachyum, Zygadenus chloranthus, 

 Rumex venosus, Oxybaphus hirsutus, Ranunculus cardiophyllus, Polanisia 

 trachysperma, Chamcerhodos erecta, Oxytropis Lambertii, Hedysarum 

 Mackenzii, Potentilla flabelliformis, Heuchera hispida, Linum Lewisii, 

 Malvastrum coccineum, Oenothera triloba, 0. serrulata, 0. pallida, Gaura 

 coccinea, Solanum triflorum, Pentstemon acuminatus, P. procerus, 

 Orobanche fasciculata, Liatris punctata, Gutierrezia Sarothrce, Chrysopsis 

 villosa, Solidago missouriensis, S. rigida, Aplopappus lanceolata, A. 

 acaulis, Townsendia exscapa, Aster angustus, Erigeron ccespitosus, E. 

 pumilus, Antennaria aprica, Helianthus petiolaris, H. giganteus, Gaillardia 

 aristata, Arnica pedunculata, Senecio integerrimus, Cirsium Drummondii, 

 Lactuca pulchella. 



Rocky Mountain Foothills. A great number of prairie species 

 reach a considerable altitude in the foothills of the Rocky Mountains. 

 On the other hand, a number of sub-alpine forms descend practically 

 to the prairie, the result being that at the base of the foothills, 

 where the two types of floras intermingle, the vegetation is very rich 

 in species. As the foothills are ascended the prairie forms gradually 

 disappear and are replaced by mountain species. The vegetation in 

 general becomes more luxuriant in appearance, the herbaceous plants 

 grow taller, shrubs begin to form an important feature in the flora and 

 real forests are established. Besides typical mountain and prairie forms, 

 the following species may be considered as characteristic of the foothills: 

 Stipa Richardsonii, Avena striata, Bromus Porteri, Elymus dasystachys, 

 Eriogonum subalpinum, Arenaria capillaris, Aquilegia brevistyla, Delph- 

 inium glaucum, D. Menziesii, Thalictrum occidentale, Actasa arguta, 

 Parnassia montanensis, Spircea lucida, Oxytropis viscidulus, Hedysarum 

 sulphurescens, Geranium Richardsonii, G. incisum, Epilobium latifolium, 

 Angelica Dawsoni, A. Lyallii, Carum Gairdneri, Primula americana, 

 Lappula floribunda, Castilleja species, Lonicera glaucescens, Aster con- 



