TODD, BRENT L.1*, HENRY R. OWEN1, JANICE M. COONS2, and CHRISTINA J. HEISLER1. 1Department of Biological Sciences, Eastern Illinois University, Charleston, IL 61920; 2Department of Natural Resources and Environmental Sciences, University of Illinois, Urbana, IL 61801. - Seed germination and seedling development of Stylisma pickeringii (Patterson bindweed), an Illinois-endangered sand prairie species.
Management and reintroduction efforts of Stylisma pickeringii
(Torr.) Gray (Patterson bindweed) are limited by a lack of knowledge
about its reproductive biology, including information about its seed
germination and seedling development. The purpose of this study was to
investigate its requirements for seed germination and its seedling
development. To investigate seed requirements, seeds were harvested
from Mason County over three growing seasons (1998, 1999 and 2000).
For all three years, seeds of different colors (yellow, tan, maroon)
were counted and germinated in petri dishes at 25 C with or without
scarification. In 1999 and 2000, flowers were tagged and seeds were
collected to determine how seed age and harvest date affect seed
color. To investigate seedling development, seedlings were counted in
the field and component parts (shoot, root, and underground shoot
branching) were measured. Seed germination was different depending on
seed color with yellow being the highest (55-96%) and maroon being the
lowest (0%). Also, the seed coat inhibited germination as
scarification increased germination. Effects of seed age and harvest
date on seed color were inconclusive. The highest seedling density
recorded was 1.8 plants/m2. For seedling development, S.
pickeringii develops an extensive taproot before developing its
shoots. Its shoot branches originate 7.2 cm beneath the soil surface.
This research has provided knowledge about the seed and seedling
biology of S. pickeringii, which will be useful in the
management of this species.
Key words: Convolvulaceae, endangered plant, germination, Stylisma pickeringii