Dwarf False Indigo

Amorpha nana Nutt.; Fraser, Cat. 1813
Amorpha microphylla Pursh, Fl. Am. Sept. 466. 1814. Amorpha punctata Raf. New Fl. 3: 14. 1838.
A low shrub, rarely more than 1 m. high, glabrous or nearly so throughout; leaves numerous, crowded, 3-10 cm. long; petioles 7-10 mm. long; leaflets 13-19, oval or oblong, rounded or emarginate and mucronate at the apex, obtuse, rounded, or acute at the base, 5-12 mm. long, 3-5 mm. wide, glabrous, conspicuously punctate beneath; petiolules very short; racemes usually solitary, dense, 5-10 cm. long; calyx glabrous, 3 mm. long; lobes lanceolate, acuminate, more than half as long as the tube; banner purple, 4 mm. long, cuneate-obovate; pod 5 mm. long, straight on the back, 2.5 mm. broad, conspicuously glandular-punctate; seed oblong, 3 mm. long, brown, shining.
Type locality: Near Mandan. North Dakota.
Distribution: Manitoba and Saskatchewan to Iowa and New Mexico.

Perennial, Shrubs, Stems woody below, or from woody crown or caudex, Plants with rhizomes or suckers, Nodules present, Stems erect or ascending, Stems less than 1 m tall, Stems solid, Stems or young twigs glabrous or sparsely glabrate, Leaves alternate, Leaves petiolate, Stipules inconspicuous, absent, or caducous, Stipules membranous or chartaceous, Stipules setiform, subulate or acicular, Stipules deciduous, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets alternate or subopposite, Stipels present at base of leaflets, Leaflets 10-many, Leaves glandular punctate or gland-dotted, Leaves glabrous or nearly so, Inflorescences racemes, Inflorescences spikes or spike-like, Inflorescence axillary, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx glabrous, Corolla re duced to 1 petal, Petals separate, Petals clawed, Petals blue, lavander to purple, or violet, Banner petal ovoid or obovate, Stamens 9-10, Stamens monadelphous, united below, Stamens long exserted, Filaments glabrous, Anthers versatile, Style terete, Fruit a legume, Fruit unilocular, Fruit indehiscent, Fruit elongate, straight, Fruit oblong or ellipsoidal, Fruit exserted from calyx, Fruit glabrous or glabrate, Fruit gland-dotted or with gland-tipped hairs, Fruit 1-seeded, Seeds ovoid to rounded in outline, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.

Amorpha nana (dwarf indigo, dwarf indigobush, dwarf false indigo, fragrant indigo-bush, fragrant false indigo, dwarf wild indigo) is a 1–3-foot (30–91 cm) tall perennial shrub in the Pea family (Fabaceae) which is native to North America. It has vibrant green pinnate leaves and clusters of purple flowers. The fruits are small pods. Dwarf false indigo grows in dry prairies and rocky hillsides. Amorpha nana likes rocky and sandy soil.

Thomas Nuttall described this species for science in 1813. The species name, nana, is the botanical Latin term for "dwarf".