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Plant Identification

Melissa GravesExtension Weeds and IPM Specialist

Outline

• Basic plant parts• Characteristics used

for plant ID• Plants currently listed

on the “high priority list”

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Basic plant parts• roots• stems• internode• node• leaves• flower/fruit

• Leaves

– Arrangement– Parts– Types– Shapes– Margins

Identifying Characteristics

• Flowers

– Symmetry– Shape– Location

• Fruit types• Root systems

Identifying Characteristics

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Leaf arrangement

Alternate

Opposite

Whorled

Leaf Parts

Leaf type

Simple leaf Compound leaf

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Leaf shape

Linear leaf

Elliptic leaf

Cordate leaf

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Leaf margin

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Entire margin Lobed margin

Dentate margin Sinuate margin

Flower Symmetry

Radial Symmetry

Bilateral Symmetry

Flower Shapes

Cruciform Ligulate

Papilionaceous(Pea flower)

InflorescenceTypes

Corymb

Umbel

Head (capitulum)

Helicoid cyme

Raceme

Fruit Types

Achene

Silicle Nutlet

Root Systems

Outline

• Basic plant parts• Characteristics used

for plant ID• Plants currently listed

on the “high priority list”

Curlyleaf Pondweed

• Aquatic plant, leaves submersed

• Leaves narrowly oblong, curly margined

• Leaves clasping to stem

• Forms dense mats

Similar Species

• Bluish-green leaves with white mid-vein

• Flat-topped to umbrella-shaped clusters of yellow flowers

• 1-4 ft. tall• Purplish brown to black

teardrop-shaped seeds

Dyer’s Woad

Photos by Steve Dewey, Utah State University, Bugwood.org

Oregon State University uspest.org

Missouri Flora www.missouriplants.com

Michael L. Charters www.calflora.net

Tumblemustard•Unbranched lower stem,

bushy upper stem•Lower leaves broad and

divided almost to mid-vein•Upper leaves with narrow,

linear lobes•Flowers white to pale

yellow

Similar Species

Similar Species

Western Wallflower (Native)•Basal leaves spreading,

linear-elliptical shaped•Leaf margins toothed (dentate)•Leaf surface with fine

hairs•Flowers bright yellow to

yellow-orange•Inflorescence tight, terminal

raceme National Park Service www.nps.gov

National Park Service www.nps.gov

Similar Species

Yellow Alyssum•Stems branching at base,

3-10 inches in height•Short, narrow leaves•Stems and leaves covered

with fine hairs•Flowers white to pale

yellow•Inflorescence tight, terminal

raceme

Mark Turner www.pnwflowers.com

Wikipedia www.commons.wikipedia.org

Matt Lavin gemini.oscs.montana.edu

Eurasian Watermilfoil

• Aquatic perennial• 4 whorled leaves at each stem

joint• >14 paired leaflets/leaf give

“feathery” appearance• Foliage does not collapse when

removed from water• Inconspicuous pink flowering

spike above water surface• Stem width twice as wide below

flower spike

Native WatermilfoilsDistinguishing from Eurasian

• Stem width remains constant below flowering spike

• Sparse branching near water surface

Short-spike– <14 paired leaflets/leaf

Whorl-leaf (western)– Bracts longer than flowers

Drawings by Hilary Parkinson, MSU

Flowering Rush

• Aquatic perennial• Creeping rhizomes and

bulblets (not in PNW)• Erect or floating leaves,

3 ft. long and ½ inch wide

• Triangular cross-section• Umbrella-shaped

clusters of pink to white flowers with 3 petals

Photos by Leslie Mehrhoff, Univ. of CT, Bugwood.org

Knotweed Complex• Japanese, Giant, Himalayan

– Separated by leaf shape and size

• Hollow, smooth, jointed stems• Base of stem surrounded by membranous

sheath• Up to 20 ft. tall (depending on species)• Small greenish-white flowers in sprays

Photo by Leslie Mehrhoff, Univ. of CT, Bugwood.org

Purple Loosestrife

• Height often 6-8 feet• Leaves smooth margined;

either opposite or whorled on stem• Flowers rose-purple with

5-7 petals• Inflorescence is a long terminal raceme• Typically found in moist or

marshy sites

Elizabeth J. Czarapata dnr.wi.gov

Elizabeth J. Czarapata dnr.wi.gov

Kentucky Division of Forestry www.forestry.ky.gov

Similar Species

Fireweed (Native)• Up to 9 feet tall• Leaves lance-shaped,

up to 8 inches long• Flowers rose to purple

(4 petals); inflorescence

a long terminal raceme• Flowers have linear

bractsJ.K. Lindsey www.commanster.eu

Walter Siegmund en.wikipedia.org

University of Northern British Columbiaweb.unbc.ca

Matt Lavin gemini.oscs.montana.edu

Rush Skeletonweed• “dandelion from hell”• Sharp, deeply

toothed rosette leaves

• Yellow flower• Downward bent,

coarse hairs on lower stem

Gary Old, Bugwood.org

Utah St. University, Bugwood.org

Gary Piper, Washington State Univ., Bugwood.org

Brian Peterson www.tolweb.org

National Park Service www.nps.gov

Jim Pisarowicz www.nps.gov

Similar Species

Skeletonweed • Up to 18 inches tall• Stems lacking hairs• Leaves small, linear, upper leaves reduced to awl-like projections• Flowers light purple•Basal leaves absent

Scotch Broom• Woody shrub, up to

10 ft tall• Bright yellow pea

flowers• Inflorescences

terminal and axillary• Trifoliate leaves,

entire leaflets• Seed pods only hairy

on the margins

Similar Species

Striated Broom • Currently found in California and Oregon• Bright yellow pea flowers• Terminal inflorescence• Trifoliate leaves, entire leaflets• Seed pods very hairy

Similar Species

Whitespanish Broom • Currently found in California, Oregon, and Washington• White pea flowers• Trifoliate leaves, entire leaflets• Seed pods very hairy

Similar Species

Yellow Sweetclover• Annual to short-lived perennial• Found throughout the United States• Yellow pea flowers• Trifoliate leaves, entire leaflets•Seed pods small

Photo by Steve Dewey, Utah State University

Photo by Steve Dewey, Utah State University

Photo by Mary Ellen Harte (bugwood.org)

Yellow Starthistle• Annual• Single yellow flower per

branch• ¾ -1 inch spines radiating

from flower bracts• Grayish-green foliage• Vertical leaves along stem

give stem a winged appearance

Photos by Steve Dewey, Utah State University, Bugwood.org

Similar Species

U.S. Fish & Wildlife www.fws.gov

Washington State Noxious Weed Control Board www.nwcb.wa.gov

Joseph M. DiTomaso www.invasive.org

Spotted Knapweed• Basal leaves long, very

dissected• Upper leaves narrow• Foliage gray-green, hairy• Flowers normally purple, may also be white or cream• Stiff bracts with hairy

margins and dark tips

Similar Species

Diffuse Knapweed• Stems rough, 1-2 feet

tall• Most leaves pinnately

divided• Flower heads narrow,

may be white to purple• Margins of bracts

comb-like

Montana Weed Control Association www.mtweed.org

Salt Lake County Weed Control www.weeds.slco.org

Montana Department of Agagr.mt.gov

Hydrilla

• Leaves in whorls of

3-6• Leaves strap shaped, minutely saw-toothed (serrate) margins• Tiny white flowers, rarely seen• Reproduces by stem fragmentation and tubers• Not currently found in Montana

Quiz Time

Which plant is purple loosestrife?

A B

Which plant is dyer’s woad?

A B C

Which plant is Eurasian Watermilfoil?

A B

Additional Resources

• Bugwood Network (http://wiki.bugwood.org/Main_Page)• High Plains IPM (http://wiki.bugwood.org/HPIPM:Main_Page)• Montana Extension (http:/www.msuextension.org)• Montana Weed Control Association (MWCA website www.mtweed.org/ )• Schutter Diagnostic Lab (http://diagnostics.montana.edu)• USDA Plants Database (http://plants.usda.gov)• Weeds of the West. Whitson, T.D. et al. 2006.

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Questions?

For more information contact:Melissa GravesExtension Weeds and IPM Specialist(406)994-6297; melissa.graves@montana.edu