Baptisia

Authority

Isely, Duane. 1981. Leguminosae of the United States. III. Subfamily Papilionoideae: tribes Sophoreae, Podalyrieae, Loteae. Mem. New York Bot. Gard. 25 (3): 1-264.

Family

Fabaceae

Scientific Name

Baptisia

Description

Species Description - Commonly robust, perennial herbs with solitary or clustered stems .5-2 m from woody crowns or subrhizomatous caudices. Lower nodes leafless. Leaves palmately trifoliolate (-simple), petioled or sessile, estipellate, commonly blackening in drying; leaflets usually obovate to oblanceolate, tapering-sessile (-petioluled). Stipules dimorphic, the lowermost clasping, the remainder either subfoliaceous, conspicuous, and persistent, or subulate and quickly caducous. Flowers in terminal racemes or 1-3 in leaf-axils; bracts either subfoliaceous and persistent, or subulate and caducous; bracteoles absent in most species. Calyx campanulate, with 4 subequal lobes .6-1 r, the upper double, somewhat wider than others and subentire to emarginate (-lobes to 2 r and upper ones separate or partially so in B. calycosa). Corolla white or yellow (-lavender-purple in B. australis); standard usually ± wings and keel, suborbicular, oblate or obcordate, replicate- or implicate-reflexed (-not reflexed), cuneate or short-clawed; wings asymmetrically obovate to oblong, straight, with a conspicuous, short auricle that is often obliquely directed, commonly also with a posterior hump or spur, rugulose on upper part of auricle and (or) immediately above, claws short-medium, commonly incurved; keel petals subcarinate to obovate, broader than wings, slightly connate, rounded at apex, usually incurved 10°-30° (-straight or incurved 60°-70°), auricle parallel to the short claw. Stamens free. Pistil stipitate, glabrous or pubescent; ovary ovoid or shortly oblong, usually tapering in both directions, < style, thick-walled; ovules 4-30; style confluent, slender-tapering, often proximally pubescent, variously incurved; stigma minute. Legume stipitate, inflated or turgid, globose, ovoid, cylindric, or asymmetrically-lanceolate, usually conspicuously beaked, persistent, slowly dehiscent; valves membranous to ligneous, usually slowly and inelastically separating by both sutures, and separately persistent, sometimes to the next year. Seeds numerous.

Discussion

Crotalaria L. auct. class., pro parte. Sophora L. auct. class., pro parte. Podalyria Willd. auct. class., pro parte. Crotalopsis Michx. ex DC. Ripasia Raf. Pericaulon Raf. Lasinia Raf. Easplasia Raf. x = 9 (Turner, 1959, 1963; Turner and Fearing, 1960; Atchison, 1949; and others). The baptisias, often large, showy and common plants, are among the more conspicuous legumes, especially in the western part of their range. They are frequently abundant in pastures, apparently rarely being eaten by livestock. Baptisia lactea and B. bracteata are subjects of wildflower books, usually under the common name of False-indigo. Some species, primarily the blue-flowered B. australis, are occasionally cultivated for ornament. Baptisia, Thermopsis, and the local monotypic Pickeringia of California constitute the New World north-temperate representatives of the classic Podalyrieae. Dement and Mabry (1975) have recently considered evolution and affinities of Baptisia and Thermopsis on the basis of flavonoid chemistry. They believe that Baptisia is derived from proto-Thermopsis through species similar to B. megacarpa in the Appalachicola River area of Florida. They regard Baptisia as more “advanced evolutionarily than Thermopsis and to exhibit more ‘evolutionary vigor.’ ” Chromosome numbers have been determined for about half of the species of Baptisia. All are either n = 9 or 2n = 18. Petal shape is relatively consistent throughout the genus and of limited taxonomic usefulness. The standard monograph of Baptisia is that of Larisey (1940a) who meticulously categorized variation on the basis of herbarium material and recognized the existence of hybridization between species. The proliferation of taxa, especially in the eastern states, probably can be attributed to lack of field experience in that part of the country. The mid western species have more recently been summarized by Turner (1959) and Correll and Johnston (1970) in floristic treatments. Baptisia seems to fall into three phyletic parts: (7) two species with bracteoles, B. calycosa and B. lecontei; (2) three simple-leaved species, B. perfoliata, B. simplicifolia, and B. arachnifera; and (3) the remaining species. There are no incompatability barriers between groups 2 and 3. Groups 1 and 2 are restricted to the southeastern coastal plain while the third occurs both in the southeastern and the central states. If one applies the principle that the area of greatest total variation is the locale of origin, that of Baptisia is evidently the southeastern United States. “Typical’’ Baptisia (group 2) is distributed in two almost disjunct regions: (a) the eastern coastal plain, New England to central Florida, B. tinctoria alone extending west to Indiana, and (b) the central United States, southern Minnesota to the Gulf coast of Texas and Louisiana, east into Mississippi, eastern Tennessee and Ohio. Three species, B. tinctoria, B. alba, and B. cinerea are restricted to the east, and one, B. sphaerocarpa, to the west. The remainder compose four complexes, each with an eastern and a western vicariad unit that constitute a single species without taxonomic subdivision, or that include either a pair of closely allied species or geographic varieties (or subspecies) of one species, depending on the taxonomic philosophy of the viewer. In the following tabulation of interpretations, the primary entries are those of Isely; T. represents Turner in Correll and Johnston (1970), and annotations; and L. is Larisey (1940a), some of whose minor varieties are omitted.

Distribution

E United States w to Minnesota and Texas, barely into Canada, 15 species (30 of Larisey, 1940a).

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