MIMOSA FAMILY 453 



1. M. uncinata (Willd.) Britton. Herbs; stem 3-15 dm. long, armed with 

 recurved prickles; leaves bipinnate; pinnae 6-12; leaflets numerous, oblong, 3-6 

 mm. long, apiculate, prominently veined beneath; peduncles prickly; pod 3-15 

 cm. long, more or less densely prickly, beaked. Schrankia uncinata Willd. 

 Prairies and dry soil: Va. Fla. Tex. Colo. Plain. Je-S. 



FAMILY 64. CAESALPINIACEAE. SENNA FAMILY. 



Trees, shrubs or herbs. Leaves alternate, usually with stipules, simple or 

 compound. Flowers mostly perfect, regular or irregular. Calyx of 5, more 

 or less united sepals. Petals usually 5, imbricate, the upper one enclosed by 

 the lateral ones in the bud. Stamens 10 or fewer, filaments distinct or mona- 

 delphous. Ovary 1-celled. Fruit a 2-valved legume or indehiscent. 



Leaves bipinnate; anthers opening lengthwise. 1. HOFFMAXSEGGIA. 



Leaves simply pinnate; anthers opening by terminal pores. 2. CHAMAECRISTA. 



1. HOFFMANSEGGIA Cav. 



Herbs, sometimes somewhat woody at the base. Leaves bipinnate; leaflets 

 several to many, often glandular-punctate. Flowers perfect, racemose. Calyx- 

 lobes equalling or exceeding the tube. Petals 5, yellow or yellowish, imbricate. 

 Stamens 10, slightly declined; filaments distinct, glandular at the base; anthers 

 opening lengthwise. Pod flat, often more or less curved, few-seeded. 



Leaves, flowers, and pods with black glandular dots; pod short, straight on the back or 

 nearly so. 1 H. Jamesii. 



Leaves, flowers, and pods without glandular dots. 



Pod about 7 mm. wide, strongly arcuate. 2. H. depranocarpa. 



Pod 12-14 mm. wide, straight or nearly so. 3. H. reperis. 



1. H. Jamesii T. & G. Herb, with fusiform root; stem branched at the 

 woody base, 1-3.5 dm. high, finely pubescent and more or less glandular; leaves 

 with 5-7 pinnae, each bearing 10^20 leaflets, which are oblong or oblong-ovate, 

 3-5 mm. long, obtuse; calyx-lobes oblong or linear-oblong, 7-9 mm. long; petals 

 about 1 cm. long, clawed; pod 2.25 cm. long. Plains: Kans. Tex. Ariz.- 

 Colo. Son. My-Au. 



2. H. depranocarpa A. Gray. Herb, perennial, with a thick root; stem 

 branched, 1-2 dm. high, puberulent; leaves with 5-11 pinnae, each with 8-20 

 leaflets; these sub-falcate, nerveless, crowded; petals obovate, glandless, about 

 1 cm. long; pod 3-4 cm. long, 9-10-seeded, glabrous or minutely puberulent. 

 Plains: N.M. Colo. Ariz. Son. Je-Au. 



3. H. repens (Eastw.) Cockerell. Perennial, with a woody rootstock, 1-1.5 

 dm. high, canescent; leaves with 5-7 pinnae, each with 4-6 leaflets, which are 

 obovate, 5-7 mm. long, strigose; lower sepal oblanceolate, the rest lanceolate; 

 petals obovate, short-clawed, 8-12 mm. long; filaments hairy below, but not 

 glandular; pod flat, broad, oblong or elliptic, rarely suborbicular. Caesalpinia 

 repens Eastw. Bluffs and washes: Utah. Son. My. 



2. CHAMAECRISTA Moench. PARTRIDGE PEA, SENSITIVE 

 PEA, WILD SENSITIVE PLANT. 



Herbs or shrubs. Leaves pinnate; rachis with 1 or 2 glands at the base. 

 Flowers solitary or clustered, axillary or supra-axillary; pedicels twisted. Calyx 

 5-lobed. Corolla irregular; petals 5, one of the lateral ones (banner) and the 

 lower one (one of the wings) larger than the rest. Stamens 10, all perfect or 

 some of them reduced to staminodia; anthers unequal in size, opening by ter- 

 minal pores. Pod linear, flat, dehiscent with elastic valves. 



1. C. fasciculata (Michx.) Greene. Erect herb; stem glabrous, 3-6 dm. 

 high, glabrous; leaflets 16-28, oblong-elliptic, about 1.5 cm. long, 3 mm. wide; 

 petiolar gland sessile; peduncles supra-axillary, 3-5-flowered; sepals 

 fully equalling the petals; pods linear, pubescent, 5 cm. long, 5 mm. wide. 

 chamaecrista Am. auth. Meadows: Me Fla Mex. Colo.- 

 Je-S. 



