Clonal Growth of Lithospermum caroliniense (Boraginaceae) in Contrasting Sand Dune Habitats

Authors

Stephen G. Weller, University of California - Irvine
Kathleen H. Keeler, University of Nebraska - LincolnFollow
Barbara A. Thomson, State University of New York at Stony Brook

Date of this Version

2000

Citation

American Journal of Botany (2000) 87(2): 237-242.

Comments

Copyright 2000, Botanical Society of America. Used by permission.

Abstract

The occurrence of clonal growth of distylous Lithospermum caroliniense was investigated in a population in the Nebraska Sandhills, an area where sand dunes have been relatively stable for at least 1,500–3,000 yr, and compared to a population occurring at the Indiana Dunes, an area of active sand dune formation. Spatial autocorrelation analysis indicated the occurrence of significant clonal propagation of genetically based floral morphs at Arapaho Prairie, but not for the Indiana Dunes. Apparent clonal growth in the Sandhills population had no overall negative effect on pollen deposition or fecundity relative to the Indiana population, although in some large clones the proportion of compatible pollen grains on stigmas was lower. Clonal growth may have occurred in the Sandhills population because of the greater age and stability of the Nebraska Sandhills; infrequent establishment of seedlings permits detection of clonal growth using the spatial pattern of floral morphs. At the Indiana dunes, repeated cycles of dune formation provide conditions favoring establishment of seedlings, and sand dune succession results in disappearance of L. caroliniense before the development of clones.