The Ecological Life Cycle of Perideridia americana (Apiaceae)

Abstract

-Perideridia americana is a geophyte that is rare in Alabama, Indiana, Kentucky, Mississippi, Ohio, Oklahoma and Tennessee but not in Arkansas, Illinois, Kansas and Missouri. Shoots emerge above the soil surface in early spring, and seeds mature in early July. By the time shoots senesce in early July, a small perennating bud has formed at the top of the root, ca. 5 cm below the soil surface. This bud grew at 5 and 15/6, but not at 30/15 C. Under natural conditions, bud growth began in early October, and buds were 5 cm long by mid-March. Seeds sown in a nontemperature-controlled greenhouse in July germinated the following spring; only two seeds germinated the 2nd yr. Seeds had underdeveloped linear embryos that grew from 0.3-2.3 mm in length before germination. Cold stratification was the only requirement for full embryo growth and for breaking of seed dormancy. Thus, the seeds have morphophysiological dormancy. Flowering in most plants was delayed until the 4th or later yr after germination. The species appears to have little potential to form a persistent seed bank, and plants do not flower until they are several years old. Therefore, survival of P. americana at a site may require long-term protection.