Monographs Details: Baptisia bracteata var. laevicaulis (A.Gray ex Canby) Isely
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.
Description:Distribution and Ecology - Range as related in key. Coastal prairies and dunes, wet pastures, open pine or deciduous woodlands, roadsides, usually sandy soils but sometimes clay. March-April (-May).
Discussion:B. leucophaea var laevicaulis Gray (1873; nom. nud.); B. leucophaea var laevicaulis Gray ex Canby (1879); B. laevicaulis (Canby) Small (1898); B. bracteata var laevicaulis (Canby) Isely (1978).
B. cuneata Small (1898).
B. oxyphylla Greene (1910).
B. bushii sensu Larisey (1940) pro parte.
This is the locally abundant, southern form of Baptisia bracteata of the central states that is essentially glabrous, has broadly rhombic-cuneate leaflets and, in the southernmost part of its range, commonly shorter, even subglobose pods. Formerly, it was treated as an affiliate species, B. laevicaulis (e.g., Larisey, 1940a; Turner, 1959), but Texas authors (e.g., Correll and Johnston, 1970), with whom I heartily concur, now regard it as an intergradient variety of B. bracteata.
The passage between Baptisia bracteata vars glabrescens and laevicaulis is clinal, and authors differ in assigning material to one variety or the other. There is no hard evidence indicating that one subjective criterion is superior to others. Var laevicaulis is herein delimited (key and Map 18) rather narrowly, the intermediates being assigned to var glabrescens as explained in discussion of that variety.
“Atypical” forms of Baptisia bracteata var laevicaulis are as follows:
Variant 1. Typical var laevicaulis except lightly pubescent.
Variant 2. Lower leaflets 2.5-4.5 r; upper leaflets 1.8-3 r; i.e., this variant has the leaf dimensions of var glabrescens variant 2, but lies within the range of var laevicaulis.
Variant 3. Fruits short, 1.8-2.5 cm, subspheroid-ellipsoid; pedicels commonly short; plants sometimes divaricate-erect rather than spreading; primarily of the lower Rio Grande Valley. Probably only a portion of the plants referable to this category were detected because most specimens lack fruit.
Larisey in annotations usually identified variant 3 specimens as Baptisia bushii that, as to type, is probably B. bracteata var laevicaulis x sphaerocarpa. These far southern Texas plants, however, are not of immediate hybrid derivation because they lie beyond the range of B. sphaerocarpa. Possibly they are derivative of past introgression.
There are no morphological or known chemical (Brehm and Alston, 1964) bases for distinguishing Baptisia cuneata Small and B. oxyphylla Greene (both 1910) from B. bracteata var laevicaulis. Brehm and Alston did find two chemical races of var laevicaulis, but the populations evidently had no correlative morphological identity.
Baptisia bracteata var laevicaulis and B. sphaerocarpa form extensive hybrid swarms in southern coastal Texas, discussed in the listing of hybrids.