Baptisia lactea var. lactea

• 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 lactea var. lactea

• Description

  Distribution and Ecology - Range as given in key, possibly also adjacent Ontario (Soper, 1962). Prairie remnants, open low woodlands, swales, creek and river margins and flood plains, pastures, roadsides, railroads; in s, coastal prairies and pinelands; usually moist, heavy soils; sporadic in occurrence but locally abundant and conspicuous; occasionally cult. April-May (s); May-July (n). White false indigo.

• Discussion

  Dolichos lacteus Raf. (1817); B. lactea (Raf.) Thieret (1969). B. leucantha T. & G. (1840). B. leucantha var divaricata Larisey (1940). B. leucantha var pauciflora Larisey (1940). B. pendula var macrophylla Larisey (1940). The widely distributed Baptisia lactea var lactea is a glabrous, commonly robust plant with deciduous stipules and bracts, and large white flowers. While the pod is variable in size and shape, it differs from that of the sympatric B. bracteata and B. australis in being apically truncate or rounded rather than tapering. Baptisia lactea vars lactea and obovata are distinguished primarily by legume shape and texture, which, while variable in both varieties, are more consistent in var lactea. The usual ovule number in B. lactea var lactea is 30-35, while that of var obovata is 25-30. But some var lactea has but 10-12 ovules, and various numbers may be found even among flowers on the same plant. The western Kentucky plants are various and their disposition between varieties debatable. Larisey (1940a) referred the specimens she saw to her Baptisia pendula var macrophylla (B. lactea var obovata herein). The more ample modern material, however, mostly has var lactea fruits and is assigned to that variety. The northern prairie forms of Baptisia lactea var lactea are robust with strict branches and ample racemes. The Ozark (southern Missouri and Arkansas) and coastal plain populations include plants that are divaricately branched without a dominant main stem, and shorter racemes. Some in Louisiana and Mississippi have unusually small fruits, and Lasseigne (1973) said Louisiana B. lactea includes two kinds: (1) those with long racemes, and (2) those with short racemes and longer-stipitate, small pods. The Larisey (1940a) varieties listed above, each described from two 19th century Louisiana collections, are probably depauperate representatives of the second group. I have seen no modern collections with such small fruit. Lasseigne’s putative taxa may be real, but the features on which they are based do not invariably correlate. Baptisia lactea var lactea hybridizes with B. tinctoria, B. bracteata, and B. sphaerocarpa, as separately described. The latter species is possibly the source of pale yellowish flowers of a few specimens of B. lactea from east Texas.