Update of Praxelis clematidea, a New Exotic in Florida

Kent Williges Florida Fish & Wildlife Research Institute

Florida Fish and Wildlife Conservation Commission

Praxelis clematidea Native Distribution

Peru

Bolivia

Brazil

Paraguay Argentina

Estimated Native Range

Estimated Exotic Occurrences Estimated Native Range

Praxelis clematidea Exotic Invasion

Peru

Bolivia

Brazil

Paraguay Argentina

Adapted from Stuart Allen 2013. Weed Futures. http://weedfutures.net/

Description

• Family: Asteraceae • 13 species in the Praxelis genus; all native to South

America • Some individuals appear to overwinter as above- ground perennials (Abbott et al. 2008) • Herb or somewhat woody at the base (suffrutescent) • Opposite leaves with irregularly toothed margins • Bluish purple flowers in small clusters (discoid) • Hairy Stems • Very strong odor like cat urine when crushed

Artificial Key to Distinguish Praxelis clematidea from Similar Genera in North America North of Mexico

1. Receptacle conical (usually strongly so). 2. Pappus lacking, coroniform (flat scales fused into a crown-like structure), or of 5–6 flattened scales (sometimes 5–6 tapering setae in A. conyzoides)____ _____________________________________ Ageratum 2. Pappus of capillary bristles; bristles more than 20. 3. Bristles ca. 30; florets 35–70+; phyllaries ca. 25, subequal,

persistent______________________________________Conoclinium 3. Bristles ca. 40; florets 25–30; phyllaries 15–25, unequal,

deciduous (absence apparent in fruit)___________________ Praxelis 1. Receptacle flat to slightly convex (rarely very shallowly conical in

Fleischmannia). 4. Phyllaries deciduous, 18–65, unequal; bristles ca. 40; florets 6–75_ ________________________________________________ Chromolaena 4. Phyllaries persistent, 20–30, unequal (to rarely subequal); bristles 20–40 rarely 0 or 5), florets(10–)15–25(–50)_________________ Fleischmannia

Adapted from Abott et al. 2008

Timeline of Discovery in Florida •Orange County

•July 26, 2006, collected by LeAnn White •July 17, 2007, collected by J. Richard Abbot with Tim Burns and Melissa Clark •July 17, 2007, collected by J. Richard Abbot with Melissa Clark •March 8, 2008, collected by J. Richard Abbot with Kurt & Julie Neubig •September 10, 2008, collected by J. Richard Abbot

• Abbot et al. describes species in Journal of the Botanical Research Institute of Texas 2(1): 621 – 626. 2008 • P. clematidea included in the 3rd edition of Wunderlin and Hanson’s Guide to the Vascular Plants of Florida published in 2011

•Lake County - December 6, 2012, collected by A. Gardner and S. Smith

•Hardee County - April 17, 2013, collected by Lavonda Rogers

•Polk County - November 18, 2013, collected by C. Cook

•Manatee County - December 2, 2013, By A. Gardner

Orange Co.

Lake Co.

Orange Co.

Hardee Co.

Lake Co.

Orange Co.

Polk Co.

Hardee Co.

Lake Co.

Orange Co.

Manatee Co.

Polk Co.

Hardee Co.

Lake Co.

Orange Co.

Control • Almost nothing is known about control methods in Florida (or anywhere else for that matter)

• Herbicides suggested in the literature include Glyphosate, Fluroxypyr, Metsulfuron-methyl, and a mixture of 2,4-D and picloram. However, there is no information available regarding the effectiveness of any of these

• 3% glyphosate mixture used at Hilochee Wildlife Management Area has been effective, but Praxelis response is similar to natalgrass—easy to kill, but the population quickly rebounds from seed. Multiple treatments needed • Also noted on Hilochee WMA: Praxelis grows aggressively from seed following prescribed burns-- invaded areas previously treated for natalgrass

Vigilance is Key! • Be on the lookout for Praxelis– seems to prefer

disturbed sites especially those in proximity to orange groves

• Inspect any plants that resemble Praxelis • (i.e. Ageratum, Conoclinium, Chromolaena,

and Fleischmannia) • Report sightings to Early Detection &

Distribution Mapping System (EDDMapS) http://www.eddmaps.org/

• Submit specimens from new counties to herbaria for new county record vouchers

References Abbott, J.R., C.L. White, and S.B. Davis. 2008. Praxelis clematidea (Asteraceae), a genus and species

new for the flora of North America. Journal of the Botanical Research Institute of Texas 2(1):621-626.

Perkins, K. D. 2013. University of Florida Herbarium Collections Catalog. University of Florida

Herbarium (FLAS) (http://www.flmnh.ufl.edu/herbarium/). Florida Museum of Natural History, University of Florida, Gainesville.

USDA, ARS, National Genetic Resources Program.

Germplasm Resources Information Network - (GRIN) [Online Database]. National Germplasm Resources Laboratory, Beltsville, Maryland. URL: http://www.ars-grin.gov/cgi-bin/npgs/html/genform.pl (11 February 2014)

Wunderlin, R. P., and B. F. Hansen. 2008. Atlas of Florida Vascular

Plants (http://www.plantatlas.usf.edu/).[S. M. Landry and K. N. Campbell (application development), Florida Center for Community Design and Research.] Institute for Systematic Botany, University of South Florida, Tampa.

Allen, S. 2013. Praxelis clematidea Family Asteraceae. Weed Futures Determining Current and

Future Weed Threats. Macquarie University and the National Climate Change Adaptation Research Facility (NCCARF). Accessed 2/13/14 http://weedfutures.net/species.php?id=241&syn_id=-1&new_window=-1

Thank you! Any Questions?