Abstract Detail

Systematics

Molgo, Iwan [1], Soltis, Pamela  S. [2], Soltis, Douglas [3].

Geographical distribution of cytotypes within Callisia section Cuthbertia (Commelinaceae).

Polyploidy (genome doubling) is a speciation mechanism that is a major evolutionary force; in fact, all angiosperms have undergone at least one ancient polyploid event, and polyploidy has been a key force in generating angiosperm diversity. Polyploids within a single species are frequently recognized as cytotypes, and this treatment may mask evolutionary lineages and grossly underestimate biodiversity. To guide conservation efforts, it is essential to investigate both the evolutionary history and life-history of our study organisms. A polyploid complex, with species of conservation concern, is found in Callisia (Commelinaceae). Callisia section Cuthbertia consists of three species (Callisia graminea, C. ornata and C. rosea) that are endemic to the southeastern U.S. and have a base chromosome number of x = 6. Callisia graminea, commonly known as grassleaf roseling, has a distribution from the southern border of Virginia through central Florida. Giles (1942) discovered three ploidal levels (2x, 4x and 6x) within Callisia graminea. Callisia rosea (Vent.) D.R. Hunt is a diploid commonly known as piedmont roseling with a distribution from South Carolina to the vicinity of Jacksonville, Florida. Callisia ornata (Small) G.C. Tucker, a diploid also known as Florida scrub roseling, is endemic to central and southern Florida. We sampled from new and known populations of Callisa section Cuthbertia and investigated their ploidy by chromosome counts and flow cytometry. Distribution maps were determined based on the cytological data obtained from this study. Two disjunct populations of diploid C. graminea were discovered in Suffolk County, Virginia, and along the Fall-line in North and South Carolina. The tetraploid C. graminea has a broad distribution, which ranges from the coastal plain of North Carolina through central Florida. The rare hexaploid C. graminea was found in Lake County, Florida, and diploid C. ornata was found along the east coast of Florida. These analyses also revealed a novel polyploidy: tetraploid populations of C. ornata were detected along the west coast of Florida. This additional biodiversity in the form of extensive cytotype variation may have different ecological roles, and this hypothesis is being explored through ecological niche modeling.

1 - University Of Florida, Department Of Biology, 385 Dickinson Hall, P.O. Box 117800, Gainesville, FL, 32611-7800, USA
2 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611-7800, USA, 352/273-1964
3 - Florida Museum of Natural History, Florida Museum of Natural History, Dickinson Hall - Museum Road, Gainesville, FL, 32611, United States

Keywords:
polyploidy
Southeastern United States
Sandhill
Florida scrub.

Presentation Type: Oral Paper
Session: 21, Cooley Awards I
Location: 201/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 11:15 AM
Number: 21013
Abstract ID:513
Candidate for Awards:George R. Cooley Award