a unique mode of dehiscence, the margins remaining more or less intact and more 

 or less persistent while the valves separate from them and often break up into 

 1 -seeded sections somewhat like loments. Mimosopsis Britt. & Rose. 



A large genus of about 400 species in tropical and subtropical regions, princi- 

 pally in North America and South America. 



1. Plants with herbaceous prostrate unarmed stems 1. M. strigillosa. 



1. Plants with clambering prickly frutescent stems, never prostrate 



2. M. malacophylla. 



1. Mimosa strigillosa T. & G. Powderpuff, vergonzosa. 



Perennial herb with sprawling annual stems 1-2 (-4) m. long, usually copiously 

 furnished with stiff spreading bristlelike emergences, but these not noxious; pinnae 

 4 to 6 pairs, more or less; leaflets usually 10 to 15 pairs per pinna, linear, 

 usually 3-6 mm. long, 0.5-1 mm. broad; flowers in pink or purple globes; pod 

 oblong, 15-20 mm. long, 10-12 mm. broad, setulose, with 1 to few joints. 



In marshes, wet grasslands and openings in forests on sandy loam, in s.e. 

 Okla. {Waterfall), e. and s.e. Tex. and coastal parts of Rio Grande Plains, 

 May-Oct.; s.e. U.S. w. to Okla. and Tex.; Tam.; Parag. and Arg. 



2. Mimosa malacophylla Gray. Raspilla. 



Liane climbing in trees or forming a tangle, usually 3-4 m. high, less commonly 

 a weak-stemmed shrub, the stems armed with recurved prickles; petioles and 

 rachises with prickles also; pinnae 3 to 5 pairs; leaflets 3 to 6 pairs per pinna, 

 pubescent or glabrous, ovate to oblong or obovate, the larger ones on any plant 

 10 mm. long or longer; flowers whitish, in heads 1-2 cm. thick; legume broadly 

 linear to oblong, 40-75 mm. long, 8-10 mm. broad, stipitate, several-jointed. Incl. 

 var. glabrata Benth., M. Wootonii Standi. 



Rare in wetlands, depressions, about ponds and in woodlands along streams, 

 Rio Grande Plains of Tex., June-July; also Tam. and N. L. 



2. Neptunia Lour. 



Perennial unarmed herbs with somewhat thickened woody orangish-colored 

 taproots and few to several sprawling prostrate or decumbent annual stems (rarely 

 floating); leaves pinnately twice-compound; pinnae 2 to 1 1 pairs, with or without 

 a gland between the lowest pair of pinnae; leaflets 8 to 43 pairs per pinna, usually 

 linear to oblong or somewhat tapered toward the apex; stipules well-developed, 

 lanceolate or lance-acuminate; peduncles axillary, several cm. long, often conspic- 

 uously bracteolate; flowers small, densely crowded in round or slightly elongated 

 heads, yellow or yellow-green, often the lower flowers of the head lacking func- 

 tional genitalia or at least functional gynoecia, the upper flowers perfect; sepals 

 and petals 5 each, free above the floral cup; stamens 10 (at least in the upper 

 flowers of the head), free above the floral cup, the anthers with a small gland 

 apically between the 2 cells; fruit a thin legume, definitely stipitate, 1-5 cm. 

 long, 6-17 mm. broad, flat, promptly dehiscent; seeds few to several, elongate, 

 oriented transversely in the pod. 



A genus of 1 1 species, scattered in warm-temperature parts of the Americas, 

 Africa, Asia and Australia. 



1. Petiole glandular; flowering peduncles bearing 2 large cordate bracts 4-8 mm. 



long and 3-5 mm. wide; leaflets without raised reticulate veins; 



plants semiaquatic or terrestrial 3. N. plena. 



1. Petiole eglandular; flowering peduncles bearing 1 or 2 subulate bracts 1—3 



mm. long and 1-2 mm. wide, or bracts absent; leaflets with raised 



reticulate veins; plants terrestrial but sometimes in wetlands (2) 



1042 



