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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » National Germplasm Resources Laboratory » Research » Publications at this Location » Publication #337445

Research Project: Plant Genetic Resource Acquisition and Conservation Strategies, International Germplasm ... for the U.S. National Plant Germplasm System

Location: National Germplasm Resources Laboratory

Title: A new weed in Florida, Spermacoce latifolia, and the distinction between S. alata and S. latifolia (Spermacoceae, Rubiaceae)

item Wiersema, John
item DELPRETE, PIERO - Herbier De Guyane, Institut De Recherche Pour Le Développement (IRD)
item KIRKBRIDE, JOSEPH - Smithsonian Institute
item FRANCK, ALAN - University Of South Florida

Submitted to: Castanea
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2017
Publication Date: 8/15/2017
Citation: Wiersema, J.H., Delprete, P.G., Kirkbride, J.H., Franck, A.R. 2017. A new weed in Florida, Spermacoce latifolia, and the distinction between S. alata and S. latifolia (Spermacoceae, Rubiaceae). Castanea. 82:114-131.

Interpretive Summary: Two distinct tropical plant species of the madder family, one of which is a noxious weed, have been confused in the literature and mostly treated as a single species under the name of the non-weedy species. The scientific name of the non-weedy species, Spermacoce alata, is listed on the Federal Noxious Weed List of the United States. However, Spermacoce latifolia is the correct name of the plant that is actually the noxious weed and should be listed. The two species have sometimes been treated in the genus Borreria. Spermacoce latifolia has recently been found as an introduced plant in two locations in peninsular Florida. If these populations are not eliminated soon, this aggressive species may continue to spread across the southern United States. This report, which clarifies the taxonomic status of this weed, is important to federal and state regulatory authorities.

Technical Abstract: Spermacoce alata and S. latifolia, frequently referred to as Borreria alata and B. latifolia, were described in the 18th Century by Aublet from French Guiana. They have sometimes been treated as a single species, but are two easily distinguished species. Spermacoce alata is known from Venezuela to the Guianas and in the eastern Amazon basin north of the Rio Amazonas, and is not weedy. The native distribution of S. latifolia is from southern Mexico through Central America and throughout eastern South America to Bolivia and Paraguay, and it is naturalized in the tropical and subtropical regions of the Old World. Spermacoce latifolia is a noxious weed that has frequently been misidentified as S. alata. The first documented reports of S. latifolia in Florida are presented. Our advice is that S. latifolia should be extirpated from Florida and placed on the Federal Noxious Weed List of the United States of America. If this species is not controlled now, it may spread across the southern USA in a few years.