MEDICAGO PALCATA, A YELLOW-FLOWEEED ALFALFA. 



17 



^yith the scanty production of pollen in the case of many of the 

 flowers, may be responsible to some extent for the paucity with 

 which the seed of the species is produced. 



Leaves. — The leaves vary in shape from ovate to linear-cuneate. 

 (PI. I.) The type and stage of growth of the plant and the posi- 

 tion in which the leaves are borne on the stem all influence their 

 size and shape. During the first few weeks of growth in the spring 

 they are larger and more ovate than they are later in the season. 

 They also appear to diminish in size and become more elongated as 

 the end of the stem is approached. In general, they are more elon- 

 gated or linear than those of Medicago sativa, although there are some 



Fig. 0. — Seed oi Medicago falcata. Note the prominence of the radicle and the rough- 

 ness and irregularity as compared to those of Medicago sativa (fig. 4). (Enlarged.) 



marked exceptions, as will be noted in the illustration. A series of 

 measurements indicates the range of proportion of length to width 

 to be from 1.8 to 1 to 16 to 1. The more ovate leaves are common 

 in groups of .plants represented by S. P. I. Nos. 24454 and 20725 

 (Pis. II, C and D, and III, A and ('), while the more linear leaves 

 are abundant in the group represented by S. P. I. Nos. 20718 and 

 24455 (Pis. II, A and /i, and IV, B and C). The large leaflets are 

 approximately 27 mm. long by 12 mm. wide, and the smaller ones 

 approximately 9 mm. long by 1.5 mm. wide. The plants having the 

 larger leaflets approach Medirar/o sativa in general characteristics. 

 The margins of (lie leaves ai'c more oi- less seri'at<'.: the npex deeply 

 notched, nmcronale. or in some ca.ses nearly entire. In some leaves 

 rymw)" I'.iiii. 42S— 17 — w 



