6 NORTH AMERICAN FLORA [Volume 24 



3. Orbexilum stipulatum (T. & G.) Rydberg. 



Psoralen stipulata T. & G. Fl. N. Am. 1 : 688. 1840. 

 Lotodes stipulatum Kuntze, Rev. Gen. 194. 1891. 



A perennial; stem branched at the base, ascending, striate, glabrous or nearly so; leaves 

 3-foliolate; stipules ovate, herbaceous, fully 1 cm. long; petioles 1-3 cm. long; leaflets ovate- 

 elliptic, obtuse, mucronate, 2-5 cm. long, glabrous, not glandular-punctate, reticulate beneath; 

 peduncles 4-5 cm. long; racemes dense, short, 1-2 cm. long; bracts broadly ovate, acuminate, 

 longer than the flowers, soon deciduous; pedicels 1 mm. long; calyx sparingly strigose, not 

 glandular-punctate; tube 2.5 mm. long; upper 4 lobes lanceolate, acute, 2.5 mm. long, the low- 

 est linear-lanceolate, acuminate, 3-3.5 mm. long; corolla nearly 1 cm. long; banner broadly 

 obovate; blades of the wings oblanceolate-lunate, with a linear basal lobe, those of the keel- 

 petals two-thirds as long, broader, with a rounded basal lobe. 



Type locality: Falls of the Ohio [Indiana], 



Distribution: Indiana and Kentuckv. near the type locality. 



Illustrations: Britt. & Brown, 111. Fl./. 2098; ed. 2./. 2501. 



4. Orbexilum melanocarpum (Benth.) Rydberg. 



Psoralea melanocarpa Benth.; Hemsl. Biol. Centr. Am. Bot. 1: 234. 1880. 

 Lotodes melanocarpum Kuntze, Rev. Gen. 194. 1891. 



A perennial, shrubby at the base; stem spreading or trailing, sparingly pubescent with 

 appressed white hairs; leaves 3-foliolate; stipules 6-10 mm. long, subulate, long-acuminate; 

 petioles 3-6 cm. long; leaflets 4—7 cm. long, ovate-lanceolate, acute, mucronate, sparingly 

 pubescent on both sides, thin; peduncles about 1 dm. long; racemes about 5 cm. long; bracts 

 6 mm. long, ovate, acuminate; pedicels 1-2 mm. long; calyx sparingly strigose; tube 2 mm. long; 

 lobes linear, acuminate, 3-4 mm. long in anthesis, 5-6 mm. long in fruit; corolla 8-9 mm. 

 long, dark-purple; pod obliquely ovate, flat, about 1 cm. long, with an incurved beak; seec". 

 3-4 mm. long, reniform, dark-brown. 



Type locality: Zimapan. Hidalgo. 



Distribution: Nuevo Leon and San Luis Potosi to Hidalgo and Chiapas. 



5. Orbexilum virgatum (Nutt.) Rydberg. 



Psoralea virgala Nutt. Gen. 2: 104. 1818. 



Psoralea simplicifolia Baldw.; T. & G. Fl. N. Am. 1: 303, as synonym. 1838. 



Lotodes virgatum Kuntze, Rev. Gen. 194. 1891. 



A perennial, with a fusiform root ; stem erect, 2-6 dm. high, mostly simple, angled, glab- 

 rate, or strigose above; leaves 1-foliolate or the basal ones pinnately 3-foliolate; stipules seta- 

 ceous, 5-8 mm. long; petioles 1-2 cm. long; leaflets linear, 3-10 cm. long, 4-10 mm. wide, 

 minutely glandular-punctate, sparingly pubescent on the margins and veins; peduncles short, 

 rarely more than 1 cm. long; racemes 1-3 cm. long; bracts subulate; pedicels 1-3 mm. long; 

 calyx sparingly hirsute; tube less than 1.5 mm. long; lobes lanceolate, the lowest one 2.5 mm. 

 long, the rest 1.5 mm. long; corolla 5-6 mm. long, purple; banner broadly obovate, with blunt 

 basal lobes; blades of the wings oblong-lunate, obtuse, with a rounded basal lobe, those of the 

 keel-petals broader, without basal lobes, only slightly shorter; pod flattened, suborbicular, 

 oblique, transversely wrinkled, 5 mm. long, with a short incurved beak; seed flat, brownish- 

 black. 



Type locality: West Florida, between St. Mary's and Satilla River [southeastern Georgia]. 

 Distribution: Southern Georgia and northern Florida. 



6. Orbexilum simplex (Nutt.) Rydberg. 



Psoralea simplex Nutt.; T. & G. Fl. N. Am. 1: 303. 1838. 



Lotodes simplex Kuntze, Rev. Gen. 194. 1891. 



Psoralea palustris Bush, Rep. Mo. Bot. Gard. 17: 121. 1906. 



A perennial, with a fusiform tuberous root; stem erect, simple, 3-9 dm. high, more or less 

 strigose throughout; stipules subulate, about 1 cm. long; leaves pinnately 3-foliolate, the lower 

 petioled, the upper subsessile; petioles 5 cm. long or less; leaflets 2-7 cm. long, 5-15 mm. wide, 

 linear or linear-lanceolate, acute or mucronate, glandular-dotted above, strigose beneath; 



