90 
yellow keel: pod flat, oblong, nearly glabrous, 3 or 4-seeded, 16 to 20 mm. long, 6 mm. 
wide, narrowed toward the base. —Ravines and cafions west of the Pecos. 
3. P. Wrightii Gray. Prostrate or twining, puberulent, with slender branches: 
leaflets hastately 3-lobed, lobes very obtuse, the lateral ones sometimes angulate and 
shorter than the oblong terminal one: peduncles few to many-flowered, longer than 
the leaves: pod pendulous, flat, pubescent, 6 to 8-seeded, over 2.5 cm. long.—Moun- 
tains near El Paso, and possibly down the Rio Grande to Eagle Pass. 
4. P. retusus Benth. Prostrate (often trailing for many feet) from a very large 
root, rough-puberulent : leaflets rhombic, obtuse and retuse, rough-puberulent both 
sides: peduncles rigid, loosely many-flowered, scarcely longer than the leaves: flow- 
ers purple: pod flat, broadly oblong, somewhat pendulous and subfalcate. —Along the 
upper Rio Grande and mountain streams west of the Pecos. 
5. P. macropoides Gray. Decumbent or diffusely spreading, flexuose, thickly vil- 
lous-hirsute, from a tuberous root : leaflets oval or subrhombic, mucronate, entire, or 
angled or lobed above the middle on one side, pubescent both sides, 18 to 36 mm. long: 
peduncles many-flowered above the middle, minutely pubescent, many times longer 
than the leaves, 10 to 25 em. long: flowers with purple standard and wings and yel- 
lowish keel: pod subcompressed, torulose, deflexed, linear, puberulent, 4 to 6-seeded, 
16 to 18 mm. long, 4 mm. wide.—A rare plant in the mountains west of the Pecos. 
6. P. atropurpureus Mog. Stems twining and retrorsely pubescent: leaflets pu- 
bescent on both sides, lanceolate, dilated at base and tapering to a long narrow point, 
3.5 to 6.5 em. long; lateral ones with large acute lobe on outer side at base; terminal 
one usually 3-lobed, sometimes obscurely so: peduncles 6 to 10-flowered, 20 to 30 cm. 
long, still more elongated in fruit: flowers dark purple: pod deflexed, linear, 7 to 9- 
seeded, 7.5 em, long, 4 mm. wide.—In mountain ravines west of the Pecos. 
* * Pods straight, terete or flattish. 
7. P. helvolus L. Prostrate or climbing, branching: leaflets ovate to oblong- 
ovate or linear-oblong, with a more or less prominent rounded lobe toward the base, 
terminal leaflet 2-lobed, or some or all often entire, 12 to 40 mm. long: corolla green- 
ish-white and purplish: pod terete, nearly glabrous, 4 to 8-seeded, 5 to 7.5 em. long, 
Gmm., wide. (P. diversifolius Pers. Strophostyles angulosa Ell, )—Sandy river banks 
in eastern Texas, and reported also from the Llano and near Laredo. 
8. P. umbellatus Britton. Stems more slender: leaflets ovate to oblong-linear, 
rarely at all lobed, 2.5 cm. long or less: pod 3.5 to 5 cm. long, scarcely 4 mm. wide. 
(P, helvolus of Amer, authors, not L. Strophostyles peduncularis Ell.)—Sandy ground, 
extending from the Gulf States through the lowlands of eastern and southern Texas 
to Corpus Christi. 
9. P, pauciflorus Benth. Slender, low-climbing, pubescent: leaflets oblong-lan- 
ceolate or ovate-oblong to linear, not lobed, 2.5 cm. long: pod pubescent, flattish, 
2.5 em. long. (Strophostyles pauciflorus Watson).—River banks, “ western Texas.” 
36. VIGNA Savi. 
Twining herbs, with 3-foliolate leaves, racemose axillary yellow flow- 
ers, a 4-toothed calyx, straight keel, style bearded above, and a terete 
torulose several-seeded pod. 
1. V.luteola Benth. Annual, hirsute: leaflets ovate or ovate-lanceolate : racemes 
on stout peduncles longer than the leaves: flowers crowded : pod hirsute. (V. glabra 
Savi.)—Along the lower Rio Grande. Var. ANGUSTIFOLIA Watson has lanceolate or 
linear-lanceolate leaves. 
