24 BULLETIN 428, U. S. DEPARTMENT OF AGRICULTURE. 
far obtained. From an agronomic standpoint, groups 1 and 2 repre- 
sent plants which in their pure state may be considered of value only 
for pasturage on account of their procumbent tendencies, while 
groups 3 and 4 are sufficiently erect to be utilized for the production 
of hay. For convenience these groups may be referred to as pasture 
and hay groups, respectively. 
BOTANICAL RELATIONSHIP. 
Considerable difference of opinion exists among botanists as to 
the exact relationship which J/edicago falcata bears to the group 
of Medicagos commonly referred to as alfalfas. By many it is given 
a specific rank coordinate with Medicago sativa. By others it is 
Fie. 11.—Individual plant of Medicago falcata, S. P. I. No. 20726, a medium broad 
crowned plant, decumbent to ascending in habit of growth, representing Group IT. 
regarded as a subspecies of Medicago sativa, while some are of the 
opinion that Medicago falcata is the true species and that Medicago 
sativa is only a subspecies or a cultivated variety of it. Linneus 
(38, 39) at one time suggested the latter arrangement. 
Urban (62) divides Medicago sativa into two sections, “ M/aero- 
carpa” and “Microcarpa,”’ and places Medicago falcata under the 
former, coordinate with vulgaris, which he indicates is the common 
cultivated variety of Wfedicago sativa. 
Alefeld (7) designates common alfalfa as Medicago sativa vulgaris 
and Medicago falcata as Medicago sativa falcata. 
Ascherson and Graebner (2) follow essentially the classification 
of Urban, but Rouy and Foucaud (57), Seringe (57), and many 
