THE GEOGRAPHICAL DISTRIBUTION OF NORTH DAKOTA PLANTS 239 
Comparison with the Flora of New Mexico 
The fact that Wooton and Standley (15) have indicated the zonal dis- 
tribution for practically all the species found in New Mexico has made it 
desirable to examine the distribution of such North Dakota plants as occur 
there. A tabulation shows that 418 of the 966 North Dakota plants (43.3%) 
are recorded in New Mexico. Of these the distribution in the latter state is: 
Introduced 68 Transition 77 
Aquatic or not stated 42 Transition to Canadian 15 
Lower Sonoran 3 Transition to Hudsonian, etc. 3 
Upper Sonoran 126 Canadian or higher zones ... 11 
Sonoran to Transition 73 
(Of those listed here as Upper Sonoran, many range also in Lower 
Sonoran, but only their northward distribution is considered here.) 
Fourteen of the Sonoran species have been mentioned in a preceding 
paragraph as entering North Dakota at one or more of the three points 
where that zone touches the state. About three fourths of the number 
extend into Transition, and these it seems convenient to divide into two 
groups. The following seem to extend only part way into Transition 
(occasional over the area southwest of the Missouri or in the southern 
part of the state east of that river) : 
Myosurus minimus Gaertneria acanthicarpa 
Polanisia trachysperma Chrysothamnus graveolens 
Euphorbia serpens Stenotus armerioides 
Euphorbia glyptosperma Towns endia exscapa 
Euphorbia Geyeri Hymenopappus filifolius 
Cycloloma atriplicijolium Bahia oppositifolia 
Eurotia Janata Tetraneuris acaulis 
Parietaria pennsylvanica Helianthus petiolaris 
Plantago Purshii Tradescantia occidentalis 
Acerates viridiflora Yucca glauca 
Solanum rostratum Cyperus inflexus 
Hedeoma nana Cyperus Schweinitzii 
Lupinus pusillus Scirpus americanus 
Parosela enneandra Carex filifolia 
Strophostyles pauciflora Andropogon Hallii 
Anogra albicaulis Sorghastrum avenaceum 
Opuntia fragilis Sporobolus cryptandrus 
Opuntia polycantha Sporobolus asperifolius 
Iva axillaris Bulbilis dactyloides 
The following species of the Sonoran list extend through the greater 
part of Transition in North Dakota, most of them being common plants 
over a large part of the state : 
