The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

savanna false indigo or indigo-bush

dwarf false indigo, dwarf indigo, dwarf indigobush

Habit Shrubs, 0.3–1.4 m; arising from compact, woody root. Shrubs, (0.1–)0.3–0.6(–1) m; usually rhizomatous.
Stems

finely longitudinally grooved and ridged, gland-dotted, strigulose to glabrate.

finely longitudinally grooved and ridged, gland-dotted, strigulose to glabrate.

Leaves

(8–)12–20(–26) cm;

stipules sometimes persistent, linear or setaceous, (1–)1.5–2(–2.5) mm;

petiole (6–)8–15(–20) mm, gland-dotted, puberulent or glabrous;

rachis sparsely gland-dotted, puberulent or glabrous;

leaflets (11–)15–31(–35), stipels acicular or setaceous, 0.8–1.8 mm, petiolule 0.7–1.5(–1.8) mm, gland-dotted, mostly puberulent or glabrous, blade elliptic to oblong or ovate to suborbiculate, (10–)15–25(–35) × (7–)9–15(–18) mm, base truncate or round to subcordate, margins usually revolute, entire or inconspicuously crenulate, apex round to obtuse or emarginate, surfaces sparsely to conspicuously gland-dotted, usually glabrous or glabrate, sometimes sparsely pubescent abaxially;

midvein terminated by a slender mucro, (0.2–)0.4–1 mm.

(1.5–)3–7(–10) cm;

stipules linear or setaceous, (2–)3–5(–6.5) mm;

petiole (2–)4–8(–10) mm, usually gland-dotted, mostly strigulose, sometimes glabrous;

rachis gland-dotted, puberulent or glabrous;

leaflets (7–)13–27(–41), stipels acicular, (1–)1.5–2.5(–3) mm, petiolule 0.7–1 mm, gland-dotted, especially abaxially, mostly pubescent to glabrate, blade usually elliptic to oblong or ovate, rarely obovate to suborbiculate, (2–)6–13(–18) × (2–)3–6(–8) mm, base mostly round, margins usually somewhat revolute, entire or inconspicuously crenulate, apex round to truncate or emarginate, surfaces glabrous, margins puberulent;

midvein usually terminated by a slender mucro, (0.6–)0.8–1.2(–1.5) mm.

Racemes

(1–)3–5(–8)-branched, 10–20(–30) cm;

rachis sparsely gland-dotted, puberulent;

bracteoles linear to narrowly subulate, 1.5–2.5(–3) mm, usually eglandular, sparsely pubescent or sparsely ciliate.

unbranched, (2–)3–7(–9) cm;

rachis eglandular, usually puberulent;

bracteoles linear to narrowly spatulate, (2.5–)3–4(–5) mm, eglandular, puberulent.

Pedicels

0.4–1 mm, eglandular, sparsely pubescent.

1–2(–2.5) mm, eglandular, usually puberulent.

Flowers

calyx tube turbinate to narrowly campanulate or cylindric, 1.7–2.2 mm, distal 1/3–2/3 rarely gland-dotted, glabrous;

lobes: abaxial lobe acuminate, slightly longer, adaxial lobes triangular to acuminate, 0.4–1.2(–1.5) mm, margins densely ciliate;

banner bright blue, broadly obovate to obcordate, (4–)5–6 × 3–3.5(–4) mm, distinctly clawed, margins entire or finely erose;

filaments 5–8 mm, distinct;

anthers yellow;

ovary pubescent.

calyx tube turbinate, (1.5–)1.8–2(–2.2) mm, at least distal 1/2 gland-dotted, glabrous;

lobes triangular to narrowly lanceolate, (0.8–)1–2(–2.2) mm;

banner dark reddish purple, broadly obcordate, 4.5–6 × 3.5–4.5 mm, distinctly clawed, margins finely erose, apex emarginate;

filaments 6–8 mm, connate basally 0.5–1 mm;

anthers purplish;

ovary glabrous.

Legumes

sessile or stipitate, 4–5.5 × 2–2.5 mm, margins curved outward abaxially, straight adaxially, at least distal 1/2–2/3 gland-dotted, glabrous.

sessile, 4.5–5.5 × 2–2.8 mm, margins curved outward abaxially, straight adaxially, at least distal 2/3 gland-dotted, glabrous.

Seeds

olive brown or brown, 2–2.3 × 1–1.5 mm, smooth, lustrous.

olive brown, 2.5–3 × 1–1.5 mm, reticulate.

2n

= 20.

Amorpha confusa

Amorpha nana

Phenology Flowering (May–)Jun–Jul. Flowering May–Jul.
Habitat Pine woodlands, savannas, and road banks in outer Atlantic Coastal Plain. Prairies, hillsides, buttes, sandy soils, clay soils if well-drained, in prairies, prairies on shale slopes, usually calcareous soils.
Elevation 0–50 m. (0–200 ft.) 200–2200 m. (700–7200 ft.)
Distribution
from FNA
NC; Pine woodlands; savannas; and road banks in outer Atlantic Coastal Plain
[BONAP county map]
from FNA
CO; IA; KS; MN; ND; NE; NM; OK; SD; MB
[WildflowerSearch map]
[BONAP county map]
Discussion

Amorpha confusa is known presently only from Brunswick and Columbus counties; it is believed to be extirpated in adjacent South Carolina. The taxon is a Federal species of concern and is listed as threatened in North Carolina. It is usually encountered growing in loamy soils, most often of the Foreston soil series.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Amorpha nana is listed as threatened by the state of Iowa; it is encountered more commonly in the northern and western parts of its range.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Amorpha Fabaceae > subfam. Faboideae > Amorpha
Sibling taxa
A. californica, A. canescens, A. crenulata, A. fruticosa, A. georgiana, A. glabra, A. herbacea, A. laevigata, A. nana, A. nitens, A. ouachitensis, A. paniculata, A. roemeriana, A. schwerinii
A. californica, A. canescens, A. confusa, A. crenulata, A. fruticosa, A. georgiana, A. glabra, A. herbacea, A. laevigata, A. nitens, A. ouachitensis, A. paniculata, A. roemeriana, A. schwerinii
Synonyms A. georgiana var. confusa A. microphylla
Name authority (Wilbur) S. C. K. Straub: Sorrie & Weakley, J. Bot. Res. Inst. Texas 3: 154. (2009) Nuttall: Cat. Pl. Upper Louisiana, no. 5. (1813)
Web links