Status of Baptisia Australis (Fabaceae) in Pennsylvania and the Potential Impact of Escaped Cultivated Genotypes: Preliminary Observations

Elaine Langone Center, Terrace Room

Baptisia australis (L.) R. Br. (Fabaceae) is an attractive native wildflower that is widespread in the Midwest and throughout eastern North America. The vigorous perennial habit, showy purple flowers, and historic use in textile dyes have made the species a favorite in cultivation. Many of the readily available “native varieties” are hybrids, however, with a pedigree combining up to three genetic lineages to express more robust characteristics. Use of these hybrids in residential and commercial landscape applications poses the potential for release of non-native genotypes via pollinators and seed dispersal into wild native populations. Although widespread in North America, populations of B. australis in the eastern portion of its range occur sporadically across the landscape in a variety of habitats ranging from rich woods and alluvial thickets to cedar glades and gravel bar river scours. Within Pennsylvania, two extant native metapopulations of B. australis are known: one from gravel bars and river scour grasslands along the upper Allegheny River and the other from scour zones along the Youghiogheny River. Despite both of these watersheds ultimately flowing to the Ohio River drainage, there is considerable distance between these B. australis metapopulations. The limited distribution and few remaining populations of B. australis in Pennsylvania qualifies it for state threatened conservation status. Given that the species is of conservation concern, we are interested in exploring the potential impact on native populations of the introduction of non-native hybrid genetic material from native garden and restoration plantings. While still in its early stages, this study seeks to answer the following research questions; 1) What is the status of the remaining wild populations of B. australis in Pennsylvania? 2) What is the genetic structure of those known native populations? 3) Is there genetic evidence of non-native hybrids in the native populations? and 4) What is the relationship of population sizes to the ecological condition of the plant communities that harbor the species? Preliminary findings based on initial field surveys are presented.