The life cycle type of Grindelia lanceolata Nutt. has been described as a biennial, a short-lived monocarpic perennial, and a (polycarpic) perennial in the taxonomic literature. Plants of this species in middle Tennessee cedar glades clearly are monocarpic (J. and C. Baskin, Amer. Midl. Nat. 102: 290-299, 1979). However, field observations suggested that those from glades in northern Alabama are at least dicarpic, and further that they differ morphologically and flower later than those in Tennessee glades. The purpose of this study was to determine if differences in morphology, flowering phenology, and/or life cycle type of Tennessee and Alabama plants are retained when grown from seeds in a "common garden" - i.e., in a nonheated greenhouse in Lexington, Kentucky. Morphological differences (all statistically significant) between G. lanceolata plants from Tennessee and Alabama included: (1) size of both rosette (AL>TN) and stem (AL>TN) leaves; (2) number of secondary basal stems (TN>AL); (3) primary stem height (AL>TN); (4) number of capitula per plant (TN>AL); (5) number of ray (AL>TN) and disk (AL>TN) flowers per capitulum; (6) diameter of capitulum (AL>TN); (7) ray flower corolla length (AL>TN); and (8) length of involucral bracts (AL>TN). Tennessee plants began flowering about 1 mo earlier than Alabama plants and did not produce basal rosettes after they flowered once (in their 2nd yr), confirming that they are strictly monocarpic. Alabama plants also flowered first in their 2nd yr; however, they have produced basal rosettes (which bolted and flowered) for four consecutive years to date, confirming that they are polycarpic. These results strongly suggest genetic differences in vegetative and floral morphology, flowering phenology, and life cycle type between Tennessee and Alabama plants of G. lanceolata.

Key words: cedar glades, common garden study, flowering phenology, Grindelia lanceolata, monocarpic perennial, polycarpic perennial