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
Praxelis clematidea Exotic Invasion Peru Bolivia Brazil Paraguay Argentina Estimated Native Range Estimated Exotic Occurrences 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 aboveground 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 3 rd 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.
Lake Co. Orange Co. Hardee Co.
Lake Co. Orange Co. Polk Co. Hardee Co.
Lake Co. Orange Co. Manatee Co. Polk Co. Hardee 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
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