366 V Prairie Flora 



of its range given by Britton and by Macmillan, that it is to be found 

 only in wood-lands; but in western Minnesota, it is never found in 

 such locations. The small white lady slipper, Cypripedium candidum, 

 once common on these flat prairies, seems to have wholly disappeared. 

 Another plant of early June quite indicative of alkaline conditions is 

 Zygadenus chloranthus, with its long racemes of greenish flowers. 

 Here too, several Senecios are to be found, probably Senecio Mlsamitae 

 and Senicio plattensis. The long stemmed hawksbeard, Grepis runci- 

 nata, is to be looked for where alkali is unusually abundant. It seems 

 to be a xerophytic plant with a large thickened root from which the 

 long stems shoot up early in June. Britton's manual gives the habitat 

 of Zizia cordata as "in woods"; the "Metaspermae of the Minnesota 

 Valley" says that it grows in thickets and on gravelly banks in the 

 southeastern part of the valley, but it is common in western Minne- 

 sota on flat alkaline prairies or around the borders of prairie meadows. 

 It never grows in woods or thickets in this part of the state. The 

 characteristic dock around the margins of saline springs is Rumex 

 persicarioides. The red goosefoct, Ghenopodium rudrum, common 

 in the sea coast marshes, appears again in wet places in the alkaline 

 prairies of western Minnesota. Ranumculus septentrionalis is com- 

 mon in valleys and on the borders of alkali spots; but the character- 

 istic crowfoot of these locations is Rannunculus cyjnhalaria. Both of 

 these plants are largely progagated by stolons; but the Gymhalaria is 

 one of the finest examples of this mode of propagation. Stachys 

 palustris is common in abandoned fields where the soil is too wet and 

 alkaline for cultivation. It is quite variable and most of the leaves 

 seem to be petioled. Perhaps it should be regarded as a distinct 

 variety. In some of its forms it is very similar to Stachys teucrifoUa 

 Rydberg. The wild mint found here has generally been referred to 

 Mentha canadensis, but this species has been reduced to a variety of 

 Mentha arvensis in the seventh edition of Gray's Manual. Lithrum 

 alatum is especially abundant on the fiat sandy prairies of Swift 

 county. A Pycnanthemum is also found — probably P. virginianum. 

 It is well to remember in passing that in the region under considera- 

 tion there is very little land so impregnated with alkaline salts as not 

 to be covered with prairie grasses. There are mainly such species 

 as are found in prairie meadows, dwarfed somewhat by the inhospita- 

 ble soil. 



5. The Valley Flora. 



It has been said that the prairie fiora is deficient in species but 

 rich in individual plants. One who has journeyed for any great 

 length of time on the open prairie becomes weary of the endless repe- 

 tition of individuals, and comes out with a sense of relief upon a broad 

 river valley such as that of the Minnesota. He will not find the 

 grasses greatly different from those of the prairie meadow, unless it 

 be those of bluff sides, and these will be spoken of further on. 



On rich dry river bottoms one will find Elymus virginicus L in 

 place of E. canadensis L. On low grounds he will find Panicum 

 capillare and Echinochloa crus-galli; on river banks Eragrostis hyp- 

 noides, dwarf and creeping, and possibly in the slow river itself the 

 stately and beautiful Zizania palustris. On low valley lands the grass 



