234 
O. A. STEVENS 
Others, which occur only in the eastern part of the state, range west 
through Canada or are found in the Rocky Mountain region of the United 
States. Such are: 
Anemone virginiana Petasites sagittata 
Impatiens hiflora Vagnera racemosa 
Khamnus alnifoUa (rare) Disporum trachycarpum 
Heliopsis scahra Carex Deweyana 
Moldavica parviflora Scolochloa festucacea 
Lathyrus palustris Hystrix Hystrix 
Lathyrus venosus Dryopteris cristata 
Meihomia grandiflora Matteucia Struthiopteris 
Eastern Limits of Prairie Plants 
Many species common to the hills and higher prairie west of the Red 
River valley extend eastward into the prairie region of western and south- 
western Minnesota. Upham (12) lists about 100 species which reach their 
eastern limits there. Most of these are common prairie plants in North 
Dakota, although absent from the lower ground of the valley or found only 
in certain places as upon old lake beaches and introduced with gravel on 
railroad grades. Such are: 
Malvastrum coccineum Cymopterus acaulis 
Asclepias speciosa Gutierrezia Sarothrae 
Pentstemon alhidus Chrysopsis villosa 
Castilleja sessiliflora Sideranthus spinulosus 
MerioUx serrulata Brauneria angustifolia 
Gaura coccinea Ratibida columnaris 
Lepargyrea argentea Gaillardia i 
Anogra pallida Artemisia frigida 
Lomatium orientale 
Others, associated with these, occur much farther east, as: Erysimum 
asperum, Eleagnus argentea, and Aster ptarmicoides , 
Life-Zone Distribution 
As shown by the map (fig. i). North Dakota lies almost entirely within 
the Transition Life Zone, the Canadian approaching closely on the north- 
east, the Upper AustraP on the south and west. Of the Transition Zone, 
Merriam (9) has stated that it is "as a whole, characterized by compara- 
tively few distinctive animals and plants, but rather by the occurrence to- 
gether of southern species which here find their northern limit, and northern 
species which here find their southern limit." 
2 No attempt is made in this paper to distinguish between a humid and an arid portion 
of these zones. Sonoran as referred to on later pages is included in Upper Austral. 
