332 CONTKIBXJTIONS FEOM THE NATIONAL HEEBAEIUM. 



browsed to a small extent by cattle, but their thorns are so sharp and strong that they 

 are mostly avoided. 



4. Mimosa borealis A. Gray, Mem. Amer. Acad. n. ser. 4: 39. 1849. 



Type locality: "Hillsides, Upper Spring, on the Cimarron." Type collected by 

 Fendler (no. 181). 



Range: Northern and eastern New Mexico and western Texas. 



New Mexico: Upper Cimarron; Logan; Lincoln; Nara Visa. Mountains, in the 

 LTpper Sonoran Zone. 



5. Mimosa fragrans A. Gray, Bost. Journ. Nat. Hist. 6: 182. 1850. 

 Type locality: "Rocky soil, on the Pierdenales, " western Texas. 

 Range : Western Texas and eastern New Mexico. 



New Mexico: Guadalupe Mountains (Wooton). Dry hills and canyons, in the 

 Upper Sonoran Zone. 



A not uncommon shrub, 1 to 1.5 meters high, in the mountains of the southeastern 

 part of the State, where it is browsed by cattle, sheep, and goats. The trunk is stout, 

 and the branches rigidly divaricate. The bark is gray and the leaves very small. 

 In herbarium specimens it closely resembles the preceding species, but it is a much 

 more rigid and grayer plant, and the pods are spiny on the margins. 



68. CASSIACEAE. Senna Family. 



Herbaceous or shrubby annuals or perennials with pinnate or bipinnate, alternate, 

 usually stipulate leaves; flowers perfect, slightly irregular; calyx of 5 more or less 

 united sepals; petals 5, yellow, imbricated, the upper one innermost in bud; stamens 

 10 or fewer, distinct; pistil simple, the ovary 1-celled, becoming a legume in fruit; 

 seeds usually several. 



KEY TO THE GENERA. 



Leaves bipinnate. 



Low herbaceous plants 30 cm. high or less 1. Hoppmanseggia (p. 332). 



Large shrub over 1 meter high 2. Poinciana (p. 334). 



Leaves once pinnate. 



Corolla almost regular; some of the stamens abor- 

 tive; calyx lobes obtuse 3. Cassia (p. 334). 



Corolla irregular, the lower petals noticeably long- 

 est; all 10 stamens functional; calyx lobes 

 acuminate 4. Chamaecrista (p. 335). 



1. HOFFMAN SEGGI A Cav. 



Low herbaceous perennials from tuberous roots or a thickened woody base, the 

 bipinnate leaves with very small leaflets; plants more or less glandular, especially on 

 the flowers and fruit (one species without glands); flowers yellow or the stamens red, 

 in naked racemes, terminal, or opposite the leaves; sepals and petals 5; stamens 10; 

 pods flattened, with few or several seeds. 



KEY TO THE SPECIES. 



Calyx not oblique at the base; sepals all alike; plants without 

 sessile black glands. 

 Plants Btipitate-glandular, the inflorescence densely so; pods 



straight or but slightly curved 1. S. densiflora. 



Plants not glandular; pods strongly falcate 2. H. drepanocarpa. 



Calyx oblique at the base; lower sepals broadest; plants covered 

 with sessile black glands. 



Pods rhombic-ovate 3. H. brachycarpa. 



Pods sublunate 4. H. jamesii. 



