Whiteflower Prairie Clover

Petalostemon pilulosus Rydberg, sp. nov
A perennial; stem 4—5 dm. high, terete, finely short-pilose, tinged with red or brown, branched; leaves 2-4 cm. long, spreading; stipules subulate, 1 mm. long; rachis not margined, finely pilose; leaflets 15-19, elliptic, sparingly and finely pilose on both sides, bright-green above, glandular-dotted beneath; peduncles 2-5 cm. long; spikes dense, 2-3 cm. long, about 6 mm. thick; bracts lanceolate, attenuate into a subulate tip, longer than the calyces, pubescent; calyx densely silky, 4 mm. long; lobes lance-subulate, attenuate, equaling the tube; corolla white; blade of the banner elliptic, about 2 mm. long, the claw nearly as long; blades of the other petals oblanceolate, 2 mm. long, the claws about 0.5 mm. long; pod silky-pubescent above.
Type collected in Arizona, 1891, Nealley 237 (herb. N. Y. Bot. Gard.).

Thornbera villosa Rydberg, sp. nov
A perennial, shrubby at the base; stem 3-5 dm. high, densely long villous, terete; leaves 2-3 cm. long; stipules subulate-setaceous, about 2 mm. long; rachis densely villous; glands and stipels concealed; leaflets 13-15, oval, or obovate, densely silky-villous, 3-5 mm. long; peduncles terminal, 2-4 cm. long; spikes 2-4 cm. long, about 1 cm. thick; bracts lanceolate, acuminate, densely silky and glandular-dotted, about equaling the calyx; calyx-tube campanulate, silky-villous, with a row of brownish glands between the ribs, 2 mm. long; lobes filiform, with a lanceolate base, plumose; corolla white; blade of the banner rounded-reniform, 2 mm. long and broad, the claw 3 mm. long; blades of the other petals oblong, 3 mm. long, slightly if at all oblique at the base, the claws about 0.5 mm. long.
Tvpe collected in the Santa Rita Mountains, Arizona, 1902, Griffiths b" Thornber 130 (herb. N. Y. Bot. Card.).
Distribution: Santa Rita and Santa Catalina Mountains, Arizona.

Thornbera ordiae (A. Gray) Rydberg
Dalea albiflora var. A. Gray. PI. Wright. 2: 38. 1853. Dalea Ordiae A. Gray, Proc. Am. Acad. 17: 200. 1882. Parosela Ordiae A. Heller. Cat. N. Am. PI. ed. 2. 6. 1900.
A perennial, somewhat woody at the base; stems 3-5 dm. high, finely pubescent; leaves 2-4 cm. long, ascending; stipules filiform, 2-3 mm. long; rachis finely pubescent, sparingly glandular-punctate; stipels gland-like; leaflets 21-33, linear, more or less involute, 3-4 mm. long, sparingly pubescent, glandular-punctate beneath; peduncles 1-4 cm. long; spikes dense, 2-7 cm. long, 7-8 mm. thick; bracts lanceolate, acuminate, shorter than the calyx; calyxtube campanulate, sharply 10-ribbed, densely pilose, with a row of glands between the ribs, 2.5 mm. long; lobes subulate, 1-1.5 mm. long; corolla white; petals like those of D. albiflora; pod densely villous and glandular-dotted above, glabrate below.
Type locality: Plains near Bovie and Rucker Valley, southern Arizona. Distribution: New Mexico, Arizona, Chihuahua, and Sonora.

Thornbera leucantha Rydberg, sp. nov
A perennial, somewhat shrubby at the base; stems 3-5 dm. high, finely puberulent, often reddish; leaves 2-4 cm. long; stipules subulate, 2 mm. long; rachis finely puberulent; stipels gland-like; leaflets 21-27, linear-oblanceolate or linear, puberulent, 7-10 mm. long; peduncles 2-4cm. long; spikes dense, 2-4 cm. long, 7-8 mm. thick; bracts lanceolate, pilose and glandular-dotted, shorter than the calyx; calyx-tube campanulate, 2 mm. long, short-pilose, 10ribbed, glandular-dotted in the intervals; lobes subulate-filiform, plumose, about equaling the tube; corolla white; blade of the banner round-oval, truncate at the base, about 3 mm. long, the claw 3 mm. long; other petals obliquely oblanceolate, or oblong-oblanceolate, 3 mm. long, the claws 1.5 mm. long; pod pilose and glandular-dotted above, glabrate at the base.
Type collected near Providencia, Durango, September 11-12, 1898, E. W. Nelson 4996 (U. S. Nat. Herb. no. 333023).

Thornbera albiflora (A. Gray) Rydb. Jour. N. Y. Bot Gard. 20: 66. 1919.
Dalea albiflora A. Gray, PI. Wright. 2: 38. 1853.
Parosela albiflora Vail, Trans. N. Y. Acad. Sci. 14: 34. 1894.
A perennial, somewhat shrubby at the base; stems several, 3-6 dm. high, densely shortvillous, terete, branched; leaves 3-5 cm. long, spreading; stipules filiform, 3 mm. long; rachis villous and sparingly and minutely glandular-dotted, black; stipels represented by yellow glands; leaflets 21-31, crowded, oblong, obtuse, 5-8 mm. long, sparingly villous on both sides, glandular-dotted beneath; peduncles 2-8 cm. long; spikes dense, 1.5-6 cm. long, 8 mm. thick; bracts lanceolate, long-attenuate, usually longer than the calyx, pilose and glandular-dotted below; calyx-tube campanulate, sharply 10-ribbed, 2.5 mm. long, densely pilose, with a row of glands in the intervals; lobes lance-subulate, nearly 2 mm. long, plumose; corolla white; blade of the banner suborbicular, with a cordate base, 3 mm. long, glandular near the base, the claw 3 mm. long; blades of the other petals broadly obliquely obovate, rounded at the apex, rounded on the upper and tapering on the lower edge of the base, 2.5 mm. long, the claws 1 mm. long; pod finely and densely pubescent and glandular-dotted above, glabrous at the base.
Type locality: Hillsides on the San Pedro. Sonora. Distribution: New Mexico, Arizona, Sonora, and Chihuahua.

Perennial, Shrubs, Stems woody below, or from woody crown or caudex, Taproot present, Nodules present, Stems erect or ascending, Stems less than 1 m tall, Plants gland-dotted or with gland-tipped hairs, Stems solid, Stems or young twigs sparsely to densely hairy, Stem hairs hispid to villous, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules setiform, subulate or acicular, Stipules deciduous, Stipules free, Leaves compound, Leaves pinnately 3-foliolate, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets 3, Leaflets 5-9, Leaves glabrous or nearly so, Inflorescences spikes or spike-like, Inflorescence terminal, Bracts conspicuously present, Bracteoles present, Calyx 5-lobed, Calyx hairy, Petals separate, Corolla papilionaceous, Petals clawed, Petals white, Banner petal narrow or oblanceolate, Banner petal ovoid or obovate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens monadelphous, unit ed below, Filaments glabrous, Style terete, Fruit a legume, Fruit unilocular, Fruit indehiscent, Fruit elongate, straight, Fruit oblong or ellipsoidal, Fruit enclosed in calyx, Fruit glabrous or glabrate, Fruit hairy, Fruit gland-dotted or with gland-tipped hairs, Fruit 1-seeded, Seeds reniform, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.

Dalea albiflora, the whiteflower prairie clover or scruffy prairie clover, is a perennial subshrub or herb of the subfamily Faboideae in the pea family-(Fabaceae). It is found in the southwestern United States and Northwestern Mexico in the states of Arizona, New Mexico, Sonora, and Chihuahua.

Whiteflower prairie clover is a low-lying subshrub with horizontal spreading gray-green pinnate leaves. The flowers are vertical with multiple inflorescences; both flowers and leaves are extremely oily and resinous, and leave perfume-like odors on any surface: hands, boots, etc.