Lesquerella ludoviciana (Nutt.) S. Wats. (silvery bladderpod) is an endangered, sand prairie plant in Illinois, where its only known habitat is the Henry Allen Gleason Nature Preserve. Three colonies are found within the preserve: North Bowl – upper, North Bowl – lower, and South Bowl. Objectives were to compare seed production and germination in these colonies. Stages of plant development (seedlings, vegetative, and reproductive), flower stalks, flowers, and fruits were counted in each colony on May 4, June 1, June 16, and July 16, 2000. Seed was collected from each colony on June 1 and 16, 2000. On June 1, seed was divided into early (lower portion of the flower stalk) and late (upper portion of the flower stalk) flowering groups. On June 16, only seed of the late flowering group remained on plants. Thus, three seed lots of differing maturity were tested. Seeds were germinated in petri dishes at 25ēC in continuous light, and counted every two to three days. Seed production was estimated using reproductive plant density, fruit numbers, and seeds per fruit. The three colonies varied greatly in seed production. The North Bowl – lower produced ten times more seed than the South Bowl, and sixty times more seed than the North Bowl – upper. Differences in seed production in each colony are due to many factors including: area (South Bowl – 270 m2, North Bowl, upper – 1025 m2, North Bowl, lower – 3248 m2), density of reproductive plants (South Bowl – 1.4 plants/m2, North Bowl, upper – 0.1 plants/m2, North Bowl, lower – 1.1 plants/m2), and presence of other plant species. Overall, germination percentages ranged from 20% to 66%. No colony differences in germination were observed. For each seed lot, a different colony exhibited better germination. Thus, no differences in germination were found due to colony but the seed production differed greatly between the colonies.

Key words: Brassicaceae, endangered plants, Lesquerella ludoviciana, seed