38 LEGUMINOSiE. (PEA FAMILY.) 



3. NEGUNDO, Mcench. Box-Elder. 



Flowers dioecious. Calyx minute. Petals and disk none. Stamens 4 or 5. Ovary 

 and fruit as in Acer. Trees; leaves pinnate; sterile flowers on clustered capillary pedi- 

 cels, the fertile in drooping racemes. 



1. N. Californicum, Torr. & Gr. Usually a small tree; leaves 3-foliolate, villous; 

 leaflets ovate or oblong, acute, 3 or 4 inches long, the terminal largest and 3-5-lobed or 

 coarsely serrate, the lateral ones coarsely serrate; fruit pubescent; wings slightly 

 spreading. 



Order ANACARDIACE^ is represented by Rhus, diversiloba, Torr. & Gr. 

 (Poison Oak); and R. aromatic a, var. triloba ta, Gr. The former has striped whitish 

 nutlets; the latter, not poisonous, has red nutlets. 



Order 20. LEGUMINOSiE. 



The single and simple free pistil becoming a legume in fruit, the alternate leaves with 

 stipules and, in our genera, the papilionaceous corolla with 10 stamens, mark this order, 

 one of the largest and most important in the vegetable kingdom. 



Flowers irregular. Calyx 3-5-cleft or toothed, persistent. Corolla of 5 petals, the 

 upper larger and always external, covering the lateral pair in the bud, and these covering 

 the lower pair, which are more or less united, forming a keel which encloses the stamens 

 and pistil. Filaments 10, rarely 5, commonly united around the pistil, either all united 

 or nine and the upper one free. Ovary forming a pod with a single row of seeds attached 

 to one side; style usually inflexed or curved. In Cercis the upper petal is small and 

 enclosed by the wings. In Amorpha there is but one petal. 



§ 1. Stamens distinct. 



Leaves digitately 3-foliolate. Herbs; yellow flowers Thermopsis. 1 



Shrub; purple flowers Pickeringia. 2 



Leaves unequally pinnate; shrubby; 1 petal Amorpha. 9 



§ 2. Stamens all united into a sheath. 



Anthers of two forms; leaves digitate, more than 3 leaflets Lupinus. 3 



Anthers all alike; leaves pinnately 3-foliolate Psoralea . 8 



§ 3. Stamens diadelphous (2 sets, 9 and 1). 

 * Leaves 3-foliolate; pods small. 



Flowers capitate. Corolla persistent Trifolium. 4 



Flowers in axillary racemes or spikes. Pod globular, wrinkled Melilotus. 5 



Flowers in axillary spikes. Pod one-seeded Psoralea. 8 



Pod spirally coiled or reniform Medicago. 6 



