MEDICAGO FALCATA, A YELLOW-FLO WEEED ALFALFA. 13 



BOTANICAL DESCRIPTION AND RELATIONSHIP. 



BOTANICAL DESCRIPTION. 



The description of Medicago falcata given by Linnseus in 1753 

 (4^), when the binomial was first published, merely indicates that 

 the peduncles are racemosely arranged, that the pods are crescent 

 shaped, and that the stems are prostrate in habit of growth. This, 

 as a matter of fact, can scarcely be considered as a description, since 

 it is in reality only a part of an analytical key to certain species of 

 the genus Medicago. Various descriptions, however, have appeared 

 since that of Linnaeus. A fairly good one was published by Lamarck 

 in 1789 {31) and another by Martyn in 1792 {1^3). 



The difficulty of preparing a satisfactory description becomes at 

 once apparent upon consideration of the numerous forms of the 

 species. ]\lany of the early ones are confusing because their authors 

 failed to recognize the existence of hybrids among the forms which 

 they attempted to describe, and all of them are imperfect, since in 

 no place was a complete collection of the forms of the species avail- 

 able. Even at this time, with the work of others from which to 

 draw and with the abundant material at hand, it is far from easy 

 to prepare a description that will present a comprehensive view of 

 the species. The diversity of Medicago falcata inspires the investi- 

 gator at once with the desire to attempt a classification that will fit 

 all existing forms. However, it requires only a little investigation 

 to convince one of the hopelessness of such a task. 



In the main there are two difficulties in the way of developing a 

 satisfactory scheme of classification — the lack of consistency in the 

 combinations of characters and the practical impossibility of deter- 

 mining from one generation of plants whether a form is of pure or 

 hybrid origin. There is, however, a certain correlation of characters 

 which permits a general grouping, although intergrading forms are 

 so c(jmmon that it frequently is difficult to differentiate the mass even 

 into broad groups. 



To serve as a basis for further discussion of botanical characters 

 it seems advisable, first, to present some rather detailed data, includ- 

 ing observations and carefid measurements made in connection with 

 the study of a large number of plants secured from many sources, 

 the.se constituting a composite description of the species. Following 

 these data an attempt is made to correlate certain characters and to 

 define the principal groups and describe them in the abstract. It is 

 hoped that this method of treatment, together with illustr-ations 

 reprcxiiiced fi-om jjhotcjgraplis, will convey a I'casonably clear idea 

 of the appearance of the striking forms of Medicago falcata. 



