Synonyms

Baptisia alba var. macrophylla

  Basis for Listing

Baptisia lactea var. lactea is a long-lived, tallgrass prairie species that reaches the northwestern edge of its range in southeastern Minnesota. Historic collections of the plant indicate that it was a common component of the tallgrass prairie throughout a significant portion of its range in Minnesota prior to settlement. However, the species suffered a dramatic decline with the large-scale landscape conversion to row-crop agriculture.

The majority of B. lactea var. lactea populations remaining in the state are primarily restricted to prairie remnants in the rights-of-way of active and abandoned railroad lines throughout the region. These narrow strips were originally protected from agriculture even though adjacent lands had long since been plowed. However, the strips are now threatened as railroads switch to herbicides for maintenance, and as they abandon rail lines and sell the strips of land to adjacent landowners. Occasional populations of B. lactea var. lactea persist in some of the ditches and rights-of-way of county and township roads throughout the region as well, but they also face threats from maintenance activities such as herbicide application and mowing. Given the severe loss of its habitat, B. lactea var. lactea was listed as a special concern species in 1996.

  Description

Baptisia lactea var. lactea is a tall, robust, shrub-like, herbaceous perennial that reaches a height of 1-2 m (3.3-6.6 ft.). It is quite conspicuous when in flower, as the inflorescence is a 20-45 cm (7.9-17.7 in.) long raceme (an elongate flowering structure in which the first flowers to open are those at the bottom of the inflorescence). The flowers are about 2.5 cm (0.98 in.) in length, white in color, and have the typical legume appearance. Pollinated and fertilized flowers are eventually replaced by green pods up to 5 cm (2.0 in.) long. These eventually turn black as they ripen. Stems of the plant are smooth, glaucous, and typically green to reddish purple. The compound leaves are trifoliate, and usually grayish-green to blue-green in color.

  Habitat

Baptisia lactea var. lactea has a broad range throughout the Midwest and the southeastern United States, and there are several varieties of the species. The variety that occurs in Minnesota is primarily restricted to the Midwest. It ranges from Minnesota to Michigan and Ohio, south to Mississippi and Texas, and west into Nebraska, Kansas, and Oklahoma. This variety is found in mesic tallgrass prairies, dry, sandy prairies, savannas, and open, upland woods. Baptisia lactea var. lactea is also known to persist in old fields, pastures, lake and river shores, and road sides (Cochrane and Iltis 2000). In Minnesota, B. lactea var. lactea is most often associated with other plants of the mesic tallgrass prairie (many of them also rare) including: Andropogon gerardii (big bluestem), Sorghastrum nutans (Indian grass), Spartina pectinata (prairie cordgrass), Silphium laciniatum (compass plant), Eryngium yuccifolium (rattlesnake master), Baptisia bracteata var. glabrescens (plains wild indigo), Helianthus grosseserratus (sawtooth sunflower), Ratibida pinnata (gray-headed coneflower), Arnoglossum plantagineum (tuberous Indian plantain), and Parthenium integrifolium (wild quinine).

  Biology / Life History

Baptisia lactea var. lactea is a deep-rooted, long-lived perennial. It can be found flowering from June through July, and the flowers are pollinated by bumble bees (Bombus spp.). The grubs of the wild indigo weevil (Apion rostrum) can occasionally be found in the pods eating the seeds, while adults feed on the leaves and flowers (Haddock and Chaplin 1982).

The best time to search for B. lactea var. lactea is when the plant is at its flowering peak in June and July. The large, conspicuous flower stalk is easily visible from a distance.

  Conservation / Management

Baptisia lactea var. lactea continues to be threatened by habitat loss and degradation. While the species is able to persist in roadsides and old fields long after its associates have been lost, changing land use practices continue to threaten the populations that still remain. Populations along roadsides and in rights-of-way are impacted by increased uses of herbicides and excessive mowing. The spread of invasive species may also impact B. lactea var. lactea in the long term. Burning is an important management tool to prevent woody species succession. In anecdotal observations, populations of B. lactea var. lactea appear to expand into abandoned agricultural fields as they are burned in prairie restoration efforts.

Several programs and resources are available to land managers and landowners to help protect and manage remaining prairie parcels including the Native Prairie Bank Program, the Native Prairie Tax Exemption Program, and a prairie restoration handbook.

  Conservation Efforts in Minnesota

The Scientific and Natural Areas (SNA) program has purchased portions of railroad rights-of-way along several abandoned rail lines thereby protecting several populations of B. lactea var. lactea. One of the most prominent sites is the Wild Indigo SNA, a twelve-mile long right-of-way abandoned by the Chicago-Milwaukee Railroad. There are also a few populations protected within the boundaries of Minnesota State Parks, including Lake Louise.

  References and Additional Information

Cochrane, T. S., and H. H. Iltis. 2000. Atlas of the Wisconsin prairie and savanna flora. Wisconsin Department of Natural Resources and University of Wisconsin - Madison Herbarium Technical Bulletin No. 191, Madison, Wisconsin. 226 pp.

Haddock, R. C., and S. J. Chaplin. 1982. Pollination and seed production in two phenologically divergent prairie legumes (Baptisia leucophaea and B. leucantha). The American Midland Naturalist 108(1):175-186.

Hilty, J. 2009. Illinois Wildflowers. . Accessed 01 February 2010.

Voss, E. G. 1985. Michigan Flora. Part II: Dicots (Saururaceae-Cornaceae). Cranbrook Institute of Science Bulletin 59 and the University of Michigan Herbarium. University of Michigan, Ann Arbor, Michigan. 727 pp.