About Lespedeza leptostachya Engelm. ex A.Gray
Lespedeza leptostachya Engelm. ex A.Gray is a long-lived perennial herb that reaches up to 1 meter in height. Its leaves are compound and pubescent, each formed of three linear or linear-oblong leaflets. Whitish hairs cover the entire above-ground plant, giving it a distinctly silvery appearance. Its inflorescence is a terminal spike holding flowers that range in color from cream to yellowish or pale pink; each individual flower is only half a centimeter long. This species produces two types of flowers: cleistogamous flowers that never open, and chasmogamous flowers that open to allow insect access. Both flower types are capable of producing seed. Blooming occurs from July through September, with peak blooming in mid-July. The plant does not flower until it reaches maturity, when it is 6 to 9 years old. The fruit is a legume pod; a single plant can produce over 500 pods, but many of these do not contain viable seeds. This species is endemic to the Upper Midwest of the United States, occurring in the Upper Mississippi Valley in the states of Minnesota, Iowa, Wisconsin, and Illinois. Most of its populations are located in northern Iowa and southern Minnesota, and it is rare across its entire known range. It is federally listed as a threatened species in the United States. It grows exclusively in tallgrass prairie, primarily in dry locations. Its typical soils are gravelly, sandy, and/or calcareous, and are generally well-drained. It prefers north-facing sloped areas. It grows in association with many other prairie plant species, including Andropogon gerardi, Schizachyrium scoparium, Sorghastrum nutans, Bouteloua curtipendula, Sporobolus heterolepis, Stipa spartea, Carex pennsylvanica, Carex bicknellii, Carex muhlenbergii, Euphorbia corollata, Phlox pilosa, Amorpha canescens, Liatris aspera, Dalea purpurea, Solidago speciosa, S. graminifolia, Gentiana puberulenta, Lithospermum canescens, Sisyrinchium albidum, Baptisia leucophaea, Ionactis linariifolius, Symphyotrichum sericeum, Echinacea pallida, Polygala polygama, Viola pedatifida, and Viola pedata. It can be found growing near its relative Lespedeza capitata, which has shorter, denser flower spikes and wider leaflets. Rare hybridization between the two species has been recorded, producing hybrid plants with intermediate flower spike lengths and leaf widths.
