Outlawed!Federal Noxious Weeds: The Aquatics

U.S. Department of AgricultureAnimal and Plant Health Inspection Service

Program Aid No. 1688Issued February 2001

USDA is an equal opportunity provider and employer.

The Animal and Plant Health Inspection Ser-vice (APHIS) is responsible for preventing thespread of certain foreign weeds into and throughthe United States. Aquatic weeds pose a signifi-cant risk to the Nation’s surface water resources.Free-floating and rooted aquatic weeds can clogirrigation channels and cover lakes, threateningcrops and wildlife.

Although outlawed, some species on the FederalNoxious Weeds List have been introduced inten-tionally through aquatic garden and aquariumplant sales and distributed at swap meets.Others have come here unintentionally as con-taminants in legal shipments, in ballast water, etc.

For more information on the Federal NoxiousWeeds List, including more aquatics, visit<www.aphis.usda.gov/ppq/weeds/> on the World Wide Web.

Photo credits: The photograph of Monochoria vaginalis was taken byC. Barre Hellquist of the biology department at the MassachusettsCollege of Liberal Arts and is reproduced by permission. The photographof Caulerpa taxifolia was taken by Alexandre Meinesz, LaboratoireEnvironnement Marin Littoral, Université de Nice–Sophia Antipolis, and isreproduced by permission. The remaining images are from APHIS’ photolibrary.

Giant salviniaSalvinia auriculata complex

Anchored waterhyacinthEichhornia azurea

HydrillaHydrilla verticillata

Indian hygrophilaHygrophila polysperma

Oxygen weedLagarosiphon major

LimnophilaLimnophila sessiliflora

MonochoriaMonochoria vaginalis

CaulerpaCaulerpa taxifolia

Pinnate mosquitofernAzolla pinnata