452 BOTANY OF CROP PLANTS 



MEDICAGO HISPIDA (Toothed Bur Clover) 



Toothed bur clover (Fig. 190) is a smooth, annual plant 

 with decumbent leaves. The leaflets often have small whitish 

 and dark red spots scattered over the surface, which disap- 

 pear with age. The flowers are yellow. The pods are netted- 

 veined, twisted spirally, and spiny. The seeds are light- to 

 brownish-yellow, kidney-shaped, and about 3 millimeters 

 long. Medicago hispida reticulata and M. hispida confinis 

 are forms with spineless pods. Toothed bur clover, Medi- 

 cago hispida denticulata, is native to the northern Mediter- 

 ranean region. It is the most common bur clover grown in 

 California. It finds some use as a pasture, hay, cover and 

 green-manure crop. 



In addition to the two species of bur clover given above, 

 there are about 35 species that are not cultivated to any 

 extent. They are all native to the Mediterranean region. 

 All are warm-climate crops. 



MELILOTUS (Sweet Clover) 



Generic Description. — Sweet clovers are tall, erect, annual 

 or biennial herbs, with a fragrant odor, especially when 

 bruised. The leaves (Fig. 183, B) are pinnately three-foliate, 

 petioled, and possess large stipules and dentate leaflets, the 

 veins of which end in the teeth. The flowers are long, slender, 

 and in one-sided, axillary racemes. They are small, and 

 white or yellow. The calyx teeth are short and about equal. 

 The standard is obovate or oblong, the wings oblong, and 

 the keel short and obtuse. The stamens are diadelphous 

 (nine and one). The sessile or stalked ovary bears a single 

 thread-like style. The pods' are ovoid or globose, small, 

 indehiscent or finally 2-valved, and usually one-seeded. 

 Ordinarily, all the seeds of one year's production do not 



