Herbs, perennial, bushy, unarmed; rootstock thick or rhizomatous. Stems stiffly erect or spreading, glabrous or pubescent. Leaves alternate, odd-pinnate; stipules present or absent; petiolate, sessile, or subsessile; leaflets usually 3, rarely 1 or 2, blade margins entire, surfaces glabrous or pubescent. Inflorescences 1–30+-flowered, axillary or terminal, racemes; bracts present or absent, 2, well developed when present; bracteoles usually absent, distal to middle of pedicel when present. Flowers papilionaceous; calyx campanulate, subactinomorphic, lobes 4; corolla white, yellow, violet, or blue, petals mostly distinct, keel petals slightly connate; stamens 10, distinct; anthers dorsifixed; ovary distinctly stipitate, glabrous or pubescent. Fruits legumes, stipitate, inflated, suborbicular, lanceoloid, ellipsoid, oblong, ovoid, or cylindric, indehiscent, leathery, glabrous or pubescent. Seeds 2–30+, obovoid to ovoid. x = 9.

Distribution

c, sc, e North America.

Discussion

Species 17 (17 in the flora).

Baptisia is monophyletic and most closely related to the North American species of Thermopsis (B. L. Turner 1981; M. G. Mendenhall 1994; Wang H. C. et al. 2006). It is mostly confined to the eastern United States; B. australis var. minor and B. tinctoria barely extend into Canada. Baptisia is perhaps best known for having very distinct species that commonly hybridize, which confounded early botanists. For example, M. M. Larisey (1940) recognized 30 species in Baptisia, most of which are of hybrid origin. D. Isely (1981) provided an excellent account in which 15 species were recognized; in his account of 1998, 16 species were recognized, some with two or more varieties. Turner (2006c) provided detailed occurrence maps for the species and varieties treated here.

D. Isely (1981) provided a detailed summary of the hybridization problems in Baptisia. As documented by R. E. Alston and B. L. Turner (1962) and M. A. Kosnik et al. (1996), anywhere two species of Baptisia are found growing together or in proximity, hybrids and/or their derivatives can be expected.

Selected References

None.

Lower Taxa

Baptisia alba, Baptisia arachnifera, Baptisia australis, Baptisia bracteata, Baptisia calycosa, Baptisia cinerea, Baptisia hirsuta, Baptisia lactea, Baptisia lanceolata, Baptisia lecontei, Baptisia leucophaea, Baptisia megacarpa, Baptisia nuttalliana, Baptisia perfoliata, Baptisia simplicifolia, Baptisia sphaerocarpa, Baptisia tinctoria

Key

1	Leaflets 1.	> 2
2	Herbs pubescent; Brantley and Wayne counties, Georgia.	Baptisia arachnifera
2	Herbs glabrous; Alabama, Florida, Georgia, South Carolina.	> 3
3	Leaves not perfoliate.	Baptisia simplicifolia
3	Leaves perfoliate.	Baptisia perfoliata
1	Leaflets usually 3 (1 or 2 distally in B. sphaerocarpa).	> 4
4	Pedicels bracteolate.	> 5
5	Flowers 10–15 mm; calyces 6–7 mm, lobes ± equal to tube.	Baptisia lecontei
5	Flowers 10–14 mm; calyces 8–13 mm, lobes much longer than tube.	> 6
6	Herbs glabrous; ne Florida.	Baptisia calycosa
6	Herbs pubescent; easternmost Florida Panhandle.	Baptisia hirsuta
4	Pedicels ebracteolate.	> 7
7	Corollas dull violet to deep blue.	Baptisia australis
7	Corollas white, cream, or yellow.	> 8
8	Corollas white, cream, or pale yellow.	> 9
9	Legumes cylindric to oblong-lanceoloid, 7–10 mm wide; flowers.	Baptisia alba
9	Legumes ellipsoid-cylindric or ellipsoid-lanceoloid to lanceoloid, 12–30 mm wide; flowers 18–25 mm.	> 10
10	Racemes terminal, stiffly erect, not secund; corollas white.	Baptisia lactea
10	Racemes axillary, ascending to horizontal, secund; corollas cream or pale yellow.	Baptisia bracteata
8	Corollas usually yellow (sometimes cream or pale yellow in B. bracteata and B. megacarpa).	> 11
11	Legumes suborbicular, woody; leaflets 3 to mid stem, 1 or 2 distally.	Baptisia sphaerocarpa
11	Legumes ovoid, suborbicular, ellipsoid, lanceoloid, or ellipsoid-lanceoloid, leathery, brittle, papery, or woody; leaflets 3 throughout.	> 12
12	Corollas 12–16 mm; legumes 8–15 mm.	Baptisia tinctoria
12	Corollas (15–)18–28 mm; legumes 8–55 mm.	> 13
13	Racemes secund, axillary, 8–30-flowered.	> 14
14	Petioles 1–4 mm mid stem; c, n United States.	Baptisia leucophaea
14	Petioles 5–14 mm mid stem; se United States.	> 15
15	Bracts persistent.	Baptisia bracteata
15	Bracts deciduous.	Baptisia cinerea
13	Racemes not secund, terminal or axillary, 1–10(–12)-flowered.	> 16
16	Mid stem leaves sessile or subsessile; corollas 15–20 mm; sc United States.	Baptisia nuttalliana
16	Mid stem leaves subsessile or petiolate; corollas 18–25 mm; se United States.	> 17
17	Petioles 15–20 mm mid stem; legumes 30–40 × 20–30 mm.	Baptisia megacarpa
17	Petioles 0.1–12 mm mid stem; legumes 10–25 × 10–12 mm.	Baptisia lanceolata