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

Appalachian indigo-bush, mountain false indigo

savanna false indigo or indigo-bush

Habit Shrubs, 1–2 m; arising from compact, woody root. Shrubs, 0.3–1.4 m; arising from compact, woody root.
Stems

smooth, sparsely gland-dotted or eglandular, usually glabrous, sometimes glabrate.

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

Leaves

(10–)14–22(–30) cm;

stipules linear to linear-lanceolate, 2.5–4.5 mm, eglandular, slightly hairy or margins ciliate;

petiole (16–)20–40(–60) mm, sparsely gland-dotted or eglandular, glabrous or sparsely puberulent;

rachis sparsely gland-dotted, glabrous or, rarely, sparsely puberulent;

leaflets (9–)11–15(–19), stipels acicular to setaceous, 1.2–2 mm, petiolule 2–4(–5.5) mm, sparsely gland-dotted, usually glabrous, blade often elliptic to oblong, sometimes ovate to, rarely, orbiculate, (14–)20–45(–75) × (10–)14–28(–36) mm, base round to truncate or subcordate, margins slightly revolute, entire or slightly crenulate, apex obtuse to broadly round or emarginate, surfaces gland-dotted, mostly glabrous;

midvein terminated by a slightly swollen mucro, 0.2–0.4 mm.

(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.

Racemes

1–3(or 4)-branched, (5–)10–18(–28) cm;

rachis gland-dotted, usually glabrous;

bracteoles usually narrowly lanceolate, (0.5–)0.8–1.5(–2) mm, eglandular, puberulent, often ciliate.

(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.

Pedicels

(0.8–)1–2.5(–3) mm, eglandular, usually glabrous.

0.4–1 mm, eglandular, sparsely pubescent.

Flowers

calyx tube broadly turbinate to campanulate, 2–3(–3.2) mm, eglandular, glabrous except rim ciliate;

lobes obscure or developed, then rounded to broadly triangular-dentate, 0–0.6(–0.8) mm;

banner purplish, broadly obcordate, (4.5–)6–8(–8.5) × 4–6 mm, clawed, margins entire or erose;

filaments 8–11 mm, connate basally 3–4.5 mm;

anthers golden yellow to orange;

ovary glabrous.

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.

Legumes

sessile, (6.5–)7.5–9(–10) × (2.5–)3–4(–4.5) mm, margins distinctly curved outward abaxially, straight or nearly so adaxially, at least distal 2/3 gland-dotted, glabrous.

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.

Seeds

not seen.

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

Amorpha glabra

Amorpha confusa

Phenology Flowering May–Jul. Flowering (May–)Jun–Jul.
Habitat Dry to moist thickets and woods, pine-oak heath ridges. Pine woodlands, savannas, and road banks in outer Atlantic Coastal Plain.
Elevation (30–)400–1200 m. ((100–)1300–3900 ft.) 0–50 m. (0–200 ft.)
Distribution
from FNA
AL; GA; NC; SC; TN
[WildflowerSearch map]
[BONAP county map]
from FNA
NC; Pine woodlands; savannas; and road banks in outer Atlantic Coastal Plain
[BONAP county map]
Discussion

Amorpha glabra is listed as a species of concern in South Carolina.

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

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.)

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Amorpha Fabaceae > subfam. Faboideae > Amorpha
Sibling taxa
A. californica, A. canescens, A. confusa, A. crenulata, A. fruticosa, A. georgiana, A. herbacea, A. laevigata, A. nana, A. nitens, A. ouachitensis, A. paniculata, A. roemeriana, A. schwerinii
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
Synonyms A. georgiana var. confusa
Name authority Desfontaines ex Persoon: Syn. Pl. 2: 295. (1807) (Wilbur) S. C. K. Straub: Sorrie & Weakley, J. Bot. Res. Inst. Texas 3: 154. (2009)
Web links