Prairie Legumes 375 



or as isolated individuals in waste places or along railway rights of 

 way; and even in such, places they are being rapidly driven out by 

 more persistent vegetation. Kentucky blue grass is driving out the 

 original prairie grasses as well as the leguminous plants. 



As nearly as the writer can remember the most common of the 

 prairie legumes was Psoralea argophylla Piirsh, and it was the silvery 

 silky-white pubescence of this plant that contributed so much toward 

 giving the prairies their prevailing gray tint. It is a plant of wide 

 distribution all over the northwestern plains. 



On high rolling prairies, and on bluffs and ridges, one was sure 

 to find Psoralea esculenta Pursh, a hairy grayish looking plant with 

 the aspect of a lupine. Deep in the tough prairie sod was buried 

 its oval or oblong farinaceous root. Encased in its tough leathery 

 exterior these roots supplied a white starchy and mealy interior of 

 agreeable flavor. This plant, the tipsini or teep-se-nee of the Indians, 

 the Pomme de Terre of the French voyageur, was the source of a large 

 part of the food supply of the natives. It is said the Indians dried it 

 and made it into flour which was used for thickening soups and for 

 other purposes. The young men who followed the early breaking plows 

 on the western Minnesota prairies can testify that the roots were very 

 good eaten raw. The Pomme de Terre river received its name from 

 the abundance of this plant on the sandy prairies along its banks near 

 where it was crossed by the old Joe Brown trail. 



When Prof. Holzinger was a home missionary in Cottonwood 

 county he collected Psoralea tenuiflora Pursh, in that county, but it 

 was a rare plant. It was afterward collected between Morton and 

 Granite Falls by Prof. MacMillan. 



The common ground-plum of the Minnesota prairies was known 

 as Astragalus caryocarpus Ker. in the old manuals, and bears the same 

 name in Robinson & Fernald's New Manual. Dr. Rydberg separated 

 it from Astragalus and proposed it the new genus Geoprumnon. Prof. 

 Nelson in the New Manual of Rocky Mountain Botany leaves the plant 

 in Astragalus as did Dr. Britton, but favors the division of the old 

 species so that our plant becomes Astragalus crassicarpus Nutt. It 

 was very common in the early days, and tradition tells us that its 

 fleshy pods were frequently cooked by travelers as a substitute for 

 green peas. One writer has testified that its flavor is midway be- 

 tweeen that of green peas and asparagus. For many years back the 

 plant has been so infested with "pea bugs" that no one would care to 

 eat the dish 



The widely distributed Astragalus Carolinianus L, or A. Cana- 

 densis L. extends throughout western Minnesota but it was nowhere 

 very common. It was found on prairies, in valleys and along river 

 banks. The specific name "canadensis" is used in the new Gray's 

 Manual and by Dr. Rydberg in his Flora of Colorado, while the New 

 Manual of Rocky Mountain Botany follows Dr. Britton and Dr. Small 

 In preferring the name "carolinianus." It seems that both names ap- 

 pear in Linnaeus' "Species Plantatrum," "carolinianus" being No. 9 

 and the 6ther No. 10. 



At widely separated intervals over the prairies of the western 



