6 NATIVE LEGUMES OF NEBRASKA AND KANSAS. 



That part of Table I referring to the country east of 100 ° west longi- 

 tude is believed to be fairly representative of average conditions. The 

 parts referring to the high plains and the sand hills are so meager as to 

 be only suggestive. The counts made on the high plains were all at 

 the eastern border and were either on loess or at the transition from 

 that to the tertiary. Farther w^est many observations were made, but 

 legumes are much fewer, and the counting of much larger areas would 

 have been necessary to get results at all reliable. Here too, the desic- 

 cation of many plants in the summer makes it very difficult to secure 

 accurate counts. 



LEGUMES FORM A LARGE PART OF OUR NATIVE FLORA. 



The writer had long been familiar with the flora of this region, but 

 was not at all prepared for such results as are shown in the table. 

 After the grasses (including sedges) and possibly the composites, leg- 

 umes form a larger part of our flora than does any other group of 

 plants. 



If these figures are representative or anywhere near it, it is evident 

 that our farm lands from time immemorial have been growing a full 

 stand of legumes. Seventeen plants to the square juTd are enough to 

 fill all the soil with their roots. Most of these plants, such as Amor- 

 pha, Kulinistera, and Psoralea, have enormous root systems (and 

 these genera represent the large majority of the prairie legumes). A 

 single plant is often sufficient to fill the soil with its roots for a radius 

 of several feet, as any farmer who has plowed up Amorpha is ready 

 to testifs\ The smallest root systems are probably those of Vicia and 

 Lotus, and yet seventeen of these to the square yard would seem to be 

 sufl&cient to gather a large supply of nitrogen. 



NODULES ABUNDANT IN WILD LEGUMES. 



Many examinations were made to ascertain the prevalence of nod- 

 ules upon different species. Large numbers of tubercles were found 

 on every species examined and on nearly every individual, except 

 mature Kuhnistera. Nodules are especially plentiful on Psoralea, 

 Astragalus, Acuan, Meibomia, and Lotus. On Lotus the nodules are 

 often almost massed together on the taproot. Some difficulty was 

 experienced at first in finding tubercles on Kuhnistera, but they are 

 always in evidence on seedlings. On the old plants there is doubt 

 whether typical nodules are produced or whether the bacteria are in 

 the small, thickened roots which occur in extraordinary numbers, 

 almost in fasicles, especially on roots of the previous year's growth. 

 During the coming season an effort will be made to determine this 

 point. The efficiency of these legumes as nitrogen gatherers does not 

 seem to be open to question, however, if the universal inoculation of 

 the seedling plants is considered. 



[Cir. 31] 



