MEDICAGO FALCATA, A YELLOW-FLOWEEED ALFALFA. 



19 



Roots. — Medicago falcata differs to a considerable degree from 

 Medicago sativa in having a much more branching root system. In 

 comparatively few cases is a single taproot developed, while the 

 entire absence of the taproot proper is A'ery common. In the majority 

 of plants, however, there is a tendency toward the development of a 

 much-branched taproot and a large number of small lateral roots. 

 Meyer reports taproots of remarkable size on wild plants growing on 

 the sandy banks of the Tom River, near Tomsk, Siberia. Some of 

 these large roots were more than 2 inches in diameter at the crown 

 and more than 1 inch in diameter at a depth of 14 feet ; a few of them 

 extended to a depth of more than 33 feet. Such a taproot develop- 



Fio. 



-ilrdiijufjo falcata, S. I*. I. No. 28071, a 3-year-old plant grown at Highmore, 

 Dak. Soio the new jjlanls that have developed from true lateral roots. 



ment, however, is very uncommon in the species and occurs only in 

 sandy or h)ose soils. A peculiar root system characterized by a 

 branched taproot from which horizontal lateral roots are produced 

 is found in some forms. Tlie hiteral roots give rise to aerial shoots, 

 which develop ultimately into perfect and in some cases independent 

 plants. (Fig. 6.) This type of proliferation has been previously 

 described by the writers (.f^). It does not appear to be correlated 

 with general habit of growth or with any imj)ortant plant characters, 

 although, as far as has been observed, it is not found in plants of the 

 very low spreading habit. It is common in S. P. I. Nos. 24455, 28070, 

 28071. and 23025. The fii'st two of these numbers were introduced 



