Extension Weeds and IPM Specialist Plant Identification Melissa Graves Extension Weeds and IPM Specialist
Outline Basic plant parts Characteristics used for plant ID Plants currently listed on the “high priority list”
Basic plant parts roots stems internode node leaves flower/fruit
Identifying Characteristics Leaves Arrangement Parts Types Shapes Margins
Identifying Characteristics Flowers Symmetry Shape Location Fruit types Root systems
Leaf arrangement
Opposite Alternate Whorled
Leaf Parts
Leaf type
Simple leaf Compound leaf Simple leaf – purple loosestrife Compound leaf – Eurasian watermilfoil (note paired linear leaflets)
Leaf shape
Elliptic leaf Linear leaf Cordate leaf Purple loosestrife – linear leaf Dyer’s woad – elliptic leaf Knotweed – cordate leaf Linear leaf Cordate leaf
Leaf margin
Entire margin Lobed margin Dentate margin Sinuate margin Purple loosestrife – entire margin Rush skeletonweed - dentate margin Spotted knapweed – lobed margin Curlyleaf pondweed – sinuate margin Dentate margin Sinuate margin
Flower Symmetry
Bilateral Symmetry Radial Symmetry Actinomorphic (radial) flower. Imagine drawing multiple lines through the flower
Flower Shapes
Cruciform Ligulate Cruciform flower Papilionaceous (Pea flower)
Inflorescence Types
Corymb Umbel Dyer’s woad – corymb Oxeye daisy - head Purple loosestrife – raceme Flowering rush – umbel Blueweed – helcoid cyme
Head (capitulum) Raceme Helicoid cyme Dyer’s woad – corymb Oxeye daisy - head Purple loosestrife – raceme Flowering rush – umbel Blueweed – helcoid cyme Helicoid cyme
Fruit Types
Achene Silicle Nutlet Silicles – dyer’s woad Achene – curlyleaf pondweed Nutlets - houndstongue
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 There are several additional pondweed species found in Montana. Most however are listed as T&E by the USDA. If you feel you could have a pondweed, please send a sample to the Schutter Lab to verify species. Bottom – Alpine pondweed Middle – Illinois pondweed Top – Longleaf pondweed
Dyer’s Woad 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 Photos by Steve Dewey, Utah State University, Bugwood.org
Similar Species 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 Oregon State University uspest.org Missouri Flora www.missouriplants.com Michael L. Charters www.calflora.net
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 Matt Lavin gemini.oscs.montana.edu Mark Turner www.pnwflowers.com Wikipedia www.commons.wikipedia.org
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 Watermilfoils Distinguishing 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 bracts Matt Lavin gemini.oscs.montana.edu University of Northern British Columbia web.unbc.ca J.K. Lindsey www.commanster.eu Walter Siegmund en.wikipedia.org
Rush Skeletonweed “dandelion from hell” Sharp, deeply toothed rosette leaves Yellow flower Downward bent, coarse hairs on lower stem Utah St. University, Bugwood.org Gary Piper, Washington State Univ., Bugwood.org Gary Old, Bugwood.org
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 Brian Peterson www.tolweb.org Jim Pisarowicz www.nps.gov National Park Service www.nps.gov
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 Also called Portuguese broom.
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 Mary Ellen Harte (bugwood.org) Photo by Steve Dewey, Utah State University
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 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 Joseph M. DiTomaso www.invasive.org U.S. Fish & Wildlife www.fws.gov Washington State Noxious Weed Control Board www.nwcb.wa.gov
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 Department of Ag agr.mt.gov Montana Weed Control Association www.mtweed.org Salt Lake County Weed Control www.weeds.slco.org
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 A B Which plant is purple loosestrife?
Which plant is dyer’s woad? B C
Which plant is Eurasian Watermilfoil? 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.
Questions? For more information contact: Melissa Graves Extension Weeds and IPM Specialist (406)994-6297; melissa.graves@montana.edu