18 BULLETIJSr 428, U. S. DEPARTMENT OF AiGEICULTUEE. 



the midrib forms a ridge, while in others it is decidedly depressed, 

 being almost buried in the fleshy tissue. Prominent midribs are 

 usually of a brownish color and occur in elongated and frequently 

 quite pubescent leaves. The veins of the leaves are more nearly par- 

 allel than they are in Medicago sativa and are more symmetrical in 

 the linear than in the obovate type. The color of the leaves varies 

 from a greenish yellow to a dark bluish green, the quantity of pubes- 

 cence affecting the color to a considerable extent. An abundance of 

 pubescence which produces a greenish gray effect is especially notice- 

 able on plants that have deeply notched leaves, such as are found in 

 S. P. I. Nos. 20721 and 20722. Upon drying, the leaves of certain 

 forms develop an almost indigo-blue color. 



The abundance of leaves appears to be correlated somewhat with 

 shape, sparseness of production being found in plants where the 

 narrow type of leaf is predominant. Supernumerary leaflets are 

 much more common than in Medicago sativa^ the number of leaflets 

 frequently reaching five in certain forms, while, on the other hand, 

 two leafllets are very common in some forms. 



The petioles are far from uniform in length and the stipules vary 

 in shape from broadly triangular to linear, their margins varying 

 from deeply serrate to almost entire. 



Stems. — To only a limited extent are the stem characters corre- 

 lated with plant type. There are some cases, however, where a cor- 

 relation exists with a fair degree of consistency. In the broad- 

 crowned forms, as found in S. P. I. Nos. 20717 and 20725, the plants 

 have uniformly slender stems of greatly varying length. In the 

 ascending forms, as found in S. P. I. Nos. 20721 and 20722, the 

 stems are stiff and of medium size, while in certain decumbent plants 

 fairly stiff trailing stems are found, some reaching 4 feet in length. 

 These are common in plants of S. P. I. Nos. 24452 and 24454. Long, 

 slender stems are abundant in broad-crowned, procumbent forms, as 

 found in S. P. I. No. 24454. The plants of the bushy habit com- 

 monly have short stems. The procumbent to decumbent plants have 

 twisted, irregular stems, while the stems of bushy plants are usually 

 more regular and more nearly straight. 



The number of stems is greatest in the broad-crowned plants and 

 ranges in some cases from approximately 1,600 per plant in plants of 

 this character to 300 or less in the narrow-crowned ascending forms. 

 These data are based on plants 4 years old. Some of the stems are 

 quite pubescent, while others are smooth. They vary from numerous 

 shades of green to reddish brown, the color being more of a fixed 

 characteristic than the result of seasonal conditions. A very good 

 idea of the variation in the stems of Medicago falcata and also some 

 conception of its racemes and leaves can be gained from an examina- 

 tion of Plates II, III (5, C, and Z>), and IV. 



