MoDErATE THrEAT
Egeria densa (Brazilian.Waterweed,.Elodea,...... Anacharis) Hydrocharitaceae.(Frog’s-bit.Family)
Initial Introduction and Expansion in range Egeria densa.was.introduced.to.the.United.States.from.South.America. and.has.been.offered.for.commercial.sale.since.the.early.1900s,.when.it. was.recommended.as.a.good.“oxygenator”.plant.for.aquariums..It.is.still. one.of.the.top-selling.aquatic.plants.for.aquariums.and,.as.a.result,.is.a. common.aquatic.weed.throughout.North.Carolina..It.also.has.widespread. distribution.across.the.United.States.from.Massachusetts.to.Florida.and. west.to.California.and.the.Pacific.Northwest.. . Since.only.male.plants.have.been.found.in.the.United.States.and.no.seeds. have.been.documented,.E. densa.relies.solely.on.vegetative.reproduction.. Hardly.an.impediment.to.its.spread,.this.plant.can.readily.establish.in. natural.waters.after.escaping.human.settings..Stem.fragments.easily.break. off.of.the.plant.and.float.into.suitable.habitats..
Description and Biology •. Submersed,.freshwater.aquatic.plant.usually.1.to.2.feet.long.but.can.. . grow.to.6.feet.or.longer.and.may.be.highly.branched.forming.dense.. . mats.at.the.water.surface.. •. Leaves.usually.occur.in.whorls.of.4.to.8.(double.nodes).but.may.occur.. . in.whorls.of.3.to.6..Leaf.margins.are.minutely.serrated.and.can.only.. . be.seen.under.magnification.. •. Short.distances.between.leaf.whorls.give.plant.distinctively.leafy.. . appearance.. •. Flowers.are.on.short.stalks.about.1.inch.from.the.water,.have.3.white.. . petals,.and.usually.appear.in.the.spring.through.early.summer. •. Egeria densa.is.often.confused.with.another.invasive.exotic.species.in.. . the.same.family,.Hydrilla verticillata.(hydrilla).described.earlier.in.this.. . document..It.also.looks.like.a.larger,.more.robust.version.of.our.. . native.Elodea canadensis.(common.waterweed)..