Part 1, 1919] FABACEAE: PSORALEAE 41 



dotted; leaflets 7-11, suborbicular, 4-S mm. long, only the terminal one somewhat retuse, 

 white-tomentose on both sides and glandular-dotted beneath; spikes 2-6 cm. long; bracts 

 subulate, acuminate, gland-tipped, 4 mm. long; flowers ascending; calyx-tube white-tomen- 

 tose, more or less glandular-dotted; calyx 10-ribbed, 4 mm. long, deeply campanulate; lobes 

 oblong, 3 mm. long, obtuse; petals pale-yellow, 7-S mm. long, retuse and revolute at the 

 apex, the banner obovate, the other petals narrowly spatulate; pod ovoid, about 1 cm. long, 

 tomentose and densely glandular, the beak slender, half as long; seeds large, dark-brown. 



Type locality: Santa Margarita Island, Lower California. 

 Distribution: Islands off west coast of Lower California. 



2. Psorobatus megacarpus (S. Wats.) Rydberg. 



Dalea megacarpa S. Wats. Proc. Am. Acad. 20: 359. 1885. 



A shrub, less than 1 m. high; branches white-tomentose and conspicuously glandular- 

 pustulate with light-brown glands; leaves 5-S cm. long; stipules subulate, 1-2 mm. long, 

 becoming spinescent; rachis white-tomentose and with scattered glands; leaflets 9-13, subor- 

 bicular or round-oval, or the terminal one obcordate, more or less retuse at the apex, 5-S mm. 

 long, white-tomentose on both sides or greener above, glandular-dotted beneath; spikes sub- 

 sessile or short-penduncled, 5-15 cm. long, nearly 1 cm. thick, dense; bracts filiform-subulate, 

 4-5 mm. long, tipped with a gland, deciduous; flowers ascending; calyx white-tomentose, 

 with a few scattered glands; tube campanulate, 3-4 mm. long, scarcely ribbed; lobes 2 

 mm. long, oblong, obtuse; petals yellow, turning brown, all distinct, almost clawless, the banner 

 broadly obovate, slightly retuse, 7 mm. long, the other petals narrowly oblanceolate, 6 mm. 

 long; stamens 9, alternately longer and shorter; pod ellipsoid, about 1 cm. long, with a short 

 beak, tomentose and with numerous glands. 



Type locality: Northern Sonora. 

 Distribution: Sonora and Lower California. 



14. PSORODENDRON* Rydberg, gen. nov. 



Asagraea Baillon, Adansonia 9: 232. 1870. Not A sagraea Lindl. 1839. 

 Dalea § Xylodalca S. Wats. Proc. Am. Acad. 11: 132, in part. 1876. 



Shrubs or trees, with pinnate or simple glandular-dotted leaves; stem glabrate and gray 

 or straw-colored in age ;' branches often spinescent, mostly pubescent and somewhat glandular- 

 dotted when young; glands, especially on the peduncles, often subulate or conic. Flowers 

 racemose; rachis often more or less spinescent, subtended by two small subulate bractlets, 

 and with a deciduous bract at the base of the short pedicels. Calyx-tube turbinate, the hypan- 

 thium slightly adnate to the base of the ovary. Corolla truly papilionaceous; petals subequal 

 or the keel rarely longer, all inserted on the hypanthium, at the base of the staminal tube; 

 banner usually deeply notched at the apex, usually with two small lobes at the base of the blade; 

 blades of the wings and keel-petals similar to each other, the latter slightly united along the 

 lower edge, obliquely obovate or oval, with a conspicuous rounded basal lobe. Stamens 9 or 

 10, monadelphous. Ovary mostly 2-ovuled, in P. spinosum 4—6-ovuled. Pod more or less com- 

 pressed, longer than the calyx, long-beaked, oblique, usually with prominent sutures, conspic- 

 uously glandular-dotted. 



Type species, Dalea Johnsoni S. Wats. 



Leaves pinnate, rarely unifoliolate. 



Racemes mostly 1 -flowered; low undershrubs with creeping rootstocks. 1. P. Kingii. 



Racemes several- or many-flowered; shrubs. 



Plants densely villous-tomentose. 2. P. arborescens. 



Plants strigose or puberulent. sometimes nearly glabrous. 



Calyx-lobes shorter than the tube, very dissimilar, the upper two 

 much broader, usually twice as broad as the lowest lobe. 

 Leaflets obovate or oval. 3. P. Wheeleri. 



Leaflets oblong to lanceolate or linear. 



Leaves, calyces, and branches densely strigose-canescent 

 when young; body of the pod 10 mm. long or less. 

 Leaflets neither decurrent nor confluent; corolla deep- 

 purple. 



* From ypoipa, scab, and SevSpov, tree. 



