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Instructions: If the group of a desired species is known from experience and prior knowledge, select if from the list below. To use the Identification Key, start at criterium 1 below and follow the key until a group is found.

Group 1 -- Ferns and Horsetails

Group 2 -- Grasses

Group 3 -- Sedges

Group 4 -- Other Monocots

Group 5 -- Trees or Shrubs

Group 6 -- Dicot Herbs with Some Leaves Compound

Group 7 -- Dicot Herbs with Most Leaves Simple and Opposite

Group 8 -- Dicot Herbs with Most Leaves Simple and Alternate

Identification Key

1. Ferns or horsetails, reproducing by spores, not seeds -- Group 1

1. Plants reproducing by flowers and seeds -- Go to 2.

2. Monocots; leaves usually with parallel veins; flower parts usually in 3's or multiples -- Go to 3.

2. Dicots; leaves usually with net veins; flower parts usually in 4's or 5's or multiples -- Go to 5.

3. Flowers without sepals and petals, each flower subtended by a scale, with all the flowers arranged in spikelets -- Go to 4.

3. Flowers with sepals and petals (green or brown in Juncus), or borne on a spadix, but not arranged in spikelets -- Group 4

4. At least one or more scales at the base of each spikelet not subtending a flower; stems never triangular -- Group 2

4. All the scales of a spikelet subtending a flower; stems sometimes triangular -- Group 3

5. Trees or shrubs; stems woody -- Group 5

5. Herbs; stems not woody -- Go to 6.

6. At least some of the leaves compound; that is, divided into distinct leaflets -- Group 6

6. None of the leaves compound -- Go to 7.

7. Most or all the leaves opposite or whorled -- Group 7

7. Most or all the leaves alternate -- Group 8

Berry Bladderfern (Cystopteris bulbifera)

Field Horsetail (Equisetum arvense)

Scouringrush Horsetail (Equisetum hyemale)

Smooth Horsetail (Equisetum laevigatum)

Royal Fern (Osmunda regalis)

Marsh Fern (Thelypteris thelypteroides)

Quackgrass (Agropyron repens)

Western Wheatgrass (Agropyron smithii)

Redtop (Agrostis alba)

Carolina Foxtail (Alopecurus carolinianus)

Giant Cane (Arundinaria gigantea)

Bluejoint (Calamagrostis canadensis)

Broadleaf Uniola (Chasmanthium latifolium)

Stout Woodreed (Cinna arundinacea)

Woolly Panicum (Dichanthelium acuminatum)

Deertongue Dichanthelium (Dichanthelium clandestinum)

Barnyard Grass (Echinochloa crusgalli)

Wild Millet (Echinochloa muricata)

Canada Wildrye (Elymus canadensis)

Virginia Wildrye (Elymus virginicus)

Teal Lovegrass (Eragrostis hypnoides)

Tall Fescue (Festuca arundinacea)

Meadow Fescue (Festuca pratensis)

Fowl Mannagrass (Glyceria striata)

Foxtail Barley (Hordeum jubatum)

Little Barley (Hordeum pusillum)

Rice Cutgrass (Leersia oryzoides)

Whitegrass (Leersia virginica)

Redtop Panicum (Panicum rigidulum)

Florida Paspalum (Paspalum floridanum)

Water Paspalum (Paspalum fluitans)

Field Paspalum (Paspalum laeve)

Reed Canarygrass (Phalaris arundinacea)

Common Reed (Phragmites australis)

Annual Bluegrass (Poa annua)

Canada Bluegrass (Poa compressa)

Kentucky Bluegrass (Poa pratensis)

Faber Bristlegrass (Setaria faberi)

Yellow Foxtail (Setaria glauca)

Prairie Cordgrass (Spartina pectinata)

Prairie Wedgegrass (Sphenopholis obtusata)

Slough Sedge (Carex atherodes)

Woodland Sedge (Carex blanda)

Bush Sedge (Carex bushii)

Longhair Sedge (Carex comosa)

Fringed Sedge (Carex crinita)

Crested Sedge (Carex cristatella)

Crowfoot Sedge (Carex crus-corvi)

Fescue Sedge (Carex festucacea)

Thin-fruited Sedge (Carex flaccosperma)

Frank's Sedge (Carex frankii)

Meadow Sedge (Carex granularis)

Gray's Sedge (Carex grayi)

Thinscale Sedge (Carex hyalinolepis)

Inland Sedge (Carex interior)

Bull Sedge (Carex lanuginosa)

Hop Sedge (Carex lupulina)

Lurid Sedge (Carex lurida)

Troublesome Sedge (Carex molesta)

Muskingum Sedge (Carex muskingumensis)

Larger Straw Sedge (Carex normalis)

Beaded Broom Sedge (Carex projecta)

Broom Sedge (Carex scoparia)

Short's Sedge (Carex shortiana)

Squarrose Sedge (Carex squarrosa)

Sawbeak Sedge (Carex stipata)

Slender Sedge (Carex tenera)

Bristlebract Sedge (Carex tribuloides)

Cattail Sedge (Carex typhina)

Fox Sedge (Carex vulpinoidea)

Taperleaf Flatsedge (Cyperus acuminatus)

Redroot Flatsedge (Cyperus erythrorhizos)

Chufa Flatsedge (Cyperus esculentus)

Rusty Flatsedge (Cyperus ferruginescens)

Yellow Flatsedge (Cyperus flavescens)

Fragrant Flatsedge (Cyperus odoratus)

Green Flatsedge (Cyperus pseudovegetus)

Slender Flatsedge (Cyperus rivularis)

Strawcolored Nutsedge (Cyperus strigosus)

Three-way Sedge (Dulichium arundinaceum)

Needle Spikerush (Eleocharis acicularis)

Flat-stemmed Spikerush (Eleocharis compressa)

Blunt Spikerush (Eleocharis obtusa)

Creeping Spikerush (Eleocharis palustris)

Squarestem Spikerush (Eleocharis quadrangulata)

Small's Spikerush (Eleocharis smallii)

Common Hemicarpha (Hemicarpha micrantha)

Hardstem Bulrush (Scirpus acutus)

Olney's Bulrush (Scirpus americanus)

Green Bulrush (Scirpus atrovirens)

Woolgrass (Scirpus cyperinus)

River Bulrush (Scirpus fluviatilis)

Reddish Bulrush (Scirpus pendulus)

Softstem Bulrush (Scirpus validus)

Common Waterplantain (Alisma plantago-aquatica)

Atlantic Camass (Camassia scilloides)

Common Dayflower (Commelina communis)

Spreading Dayflower (Commelina diffusa)

Virginia Dayflower (Commelina virginica)

Northern Spiderlily (Hymenocallis occidentalis)

Common Goldstargrass (Hypoxis hirsuta)

Tapertip Rush (Juncus acuminatus)

Twinflower Rush (Juncus biflorus)

Short-fruited Rush (Juncus brachycarpus)

Soft Rush (Juncus effusus)

Inland Rush (Juncus interior)

Jointed Rush (Juncus nodosus)

Slender Rush (Juncus tenuis)

Torrey Rush (Juncus torreyi)

Nodding Ladies' Tresses (Spiranthes cernua)

Skunk Cabbage (Symplocarpus foetidus)

Hazel Alder (Alnus serrulata)

Dull-leaf Indigo (Amorpha fruticosa)

River Birch (Betula nigra)

Low Birch (Betula pumila)

American Hornbeam (Carpinus caroliniana)

Common Pecan (Carya illinoensis)

Shellbark Hickory (Carya laciniosa)

Shagbark Hickory (Carya ovata)

Sugarberry (Celtis laevigata)

Common Hackberry (Celtis occidentalis)

Button Bush (Cephalanthus occidentalis)

Leatherleaf (Chamaedaphne calyculata)

Gray Dogwood (Cornus foemina)

Red-osier Dogwood (Cornus stolonifera)

Water Willow (Decodon verticillatus)

Swamp Privet (Forestiera acuminata)

Green Ash (Fraxinus pennsylvanica)

Possumhaw Holly (Ilex decidua)

Winterberry (Ilex verticillata)

Shrubby Cinquefoil (Potentilla fruticosa)

Common Chokecherry (Prunus virginiana)

Swamp White Oak (Quercus bicolor)

Bur Oak (Quercus macrocarpa)

Swamp Chestnut Oak (Quercus michauxii)

Shumard Oak (Quercus shumardii)

Swamp Rose (Rosa palustris)

Peachleaf Willow (Salix amygdaloides)

Hoary Willow (Salix candida)

Pussy Willow (Salix discolor)

Sandbar Willow (Salix exigua)

Black Willow (Salix nigra)

American Elder (Sambucus canadensis)

Nannyberry (Viburnum lentago)

Black Haw (Viburnum prunifolium)

Arrow-wood (Viburnum recognitum)

Small-flowered Agrimony (Agrimonia parviflora)

American Potatobean (Apios americana)

Bitter Wintercress (Barbarea vulgaris)

Tickseed Sunflower (Bidens aristosa)

Devils Beggarticks (Bidens frondosa)

Pennsylvania Bittercress (Cardamine pensylvanica)

Maryland Senna (Cassia marilandica)

Spreading Chervil (Chaerophyllum procumbens)

Spotted Waterhemlock (Cicuta maculata)

Yellow Corydalis (Corydalis flavula)

Spring Avens (Geum vernum)

Narrow-leaved Paleseed (Leucospora multifida)

Birdsfoot Trefoil (Lotus corniculatus)

Cowbane (Oxypolis rigidior)

Subalpine Buttercup (Ranunculus abortivus)

Swamp Buttercup (Ranunculus septentrionalis)

Butterweed (Senecio glabellus)

Waterparsnip (Sium suave)

Purple Gerardia (Agalinis purpurea)

Common Ragweed (Ambrosia artemisiifolia)

Giant Ragweed (Ambrosia trifida)

Purple Ammannia (Ammannia coccinea)

Indianhemp Dogbane (Apocynum cannabinum)

Swamp Milkweed (Asclepias incarnata)

Purple Milkweed (Asclepias purpurascens)

Showy Milkweed (Asclepias speciosa)

Disk Water Hyssop (Bacopa rotundifolia)

Nodding Beggarticks (Bidens cernua)

False Nettle (Boehmeria cylindrica)

White Turtlehead (Chelone glabra)

Mistflower (Conoclinium coelestinum)

Virginia Buttonweed (Diodia virginiana)

Yerba de Tajo (Eclipta alba)

Purplestem Joepyeweed (Eupatoriadelphus fistulosus)

Boneset (Eupatorium perfoliatum)

Bluntleaf Bedstraw (Galium obtusum)

Dye Bedstraw (Galium tinctorium)

Small Bedstraw (Galium trifidum)

Fringed Gentian (Gentianopsis crinita)

Clammy Hedge-hyssop (Gratiola neglecta)

Sawtooth Sunflower (Helianthus grosseserratus)

Rough Sumpweed (Iva annua)

Dwarf Dandelion (Krigia cespitosa)

False Pimpernel (Lindernia anagallidea)

Moistbank Pimpernel (Lindernia dubia)

Marsh Purslane (Ludwigia palustris)

American Bugleweed (Lycopus americanus)

Rough Bugleweed (Lycopus asper)

Stalked Water Horehound (Lycopus rubellus)

Virginia Bugleweed (Lycopus virginicus)

Fringed Loosestrife (Lysimachia ciliata)

Lanceleaf Loosestrife (Lysimachia lanceolata)

Moneywort Loosestrife (Lysimachia nummularia)

Water Loosestrife (Lysimachia thyrsiflora)

Purple Loosestrife (Lythrum salicaria)

Field Mint (Mentha arvensis)

Sharp-winged Monkey-flower (Mimulus alatus)

Carpetweed (Mollugo verticillata)

Foxglove Beardtongue (Penstemon digitalis)

Beafsteak Plant (Perilla frutescens)

Smooth Phlox (Phlox glaberrrima)

Garden Phlox (Phlox paniculata)

Fog-fruit (Phyla lanceolata)

False Dragon-head (Physostegia virginiana)

Clearweed (Pilea pumila)

Common Selfheal (Prunella vulgaris)

Slender Mountain-mint (Pycnanthemum tenuifolium)

Maryland Meadow Beauty (Rhexia mariana)

Tooth-cup (Rotala ramosior)

Smooth Ruellia (Ruellia strepens)

Rose-pink (Sabatia angularis)

Blue Skullcap (Scutellaria lateriflora)

Cup-plant (Silphium perfoliatum)

Smooth Buttonweed (Spermacoce glabra)

Woundwort (Stachys palustris)

Smooth Hedge Nettle (Stachys tenuifolia)

Canada Germander (Teucrium canadense)

Marsh St. Johnswort (Triadenum walteri)

Blue Vervain (Verbena hastata)

Purslane Speedwell (Veronica peregrina)

Culver's-root (Veronicastrum virginicum)

Amaranth Tumbleweed (Amaranthus albus)

Redroot Amaranth (Amaranthus retroflexus)

Nuttall's Waterhemp (Amaranthus rudis)

Willow Amsonia (Amsonia tabernaemontana)

Rush Aster (Aster junciformis)

Calico Aster (Aster lateriflorus)

New England Aster (Aster novae-angliae)

Whitefield Aster (Aster simplex)

Fairy Aster (Aster vimineus)

Marsh Boltonia (Boltonia asteroides)

Hedge Bindweed (Calystegia sepium)

American Bellflower (Campanula americana)

Spring Cress (Cardamine bulbosa)

Purple Cress (Cardamine douglassii)

Lambsquarter (Chenopodium album)

Winged Pigweed (Cycloloma atriplicifolium)

Purpleleaf Willowweed (Epilobium coloratum)

Annual Fleabane (Erigeron annuus)

Philadelphia Fleabane (Erigeron philadelphicus)

Robin's Plantain (Erigeron pulchellus)

Rough Fleabane (Erigeron strigosus)

Narrowleaf Cottonsedge (Eriophorum angustifolium)

Grass-leaved Goldenrod (Euthamia graminifolia)

Sneezeweed (Helenium autumnale)

Purple-headed Sneezeweed (Helenium flexosum)

Cowparsnip (Heracleum lanatum)

Halberd-leaved Rosemallow (Hibiscus laevis)

Spotted Touch-me-not (Impatiens capensis)

Small White Morning-glory (Ipomoea lacunosa)

Canada Woodnettle (Loportea canadensis)

Cardinalflower (Lobelia cardinalis)

Bigblue Lobelia (Lobelia siphilitica)

Seedbox (Ludwigia alternifolia)

Winged Lythrum (Lythrum alatum)

Tiny Mouse-tail (Myosurus minimus)

Common Evening Primrose (Oenothera biennis)

Prairie Sundrops (Oenothera pilosella)

Pennsylvania Pellitory (Parietaria pensylvanica)

Ditch-stonecrop (Penthorum sedoides)

Coville's Phacelia (Phacelia ranunculacea)

Heartleaf Plantain (Plantago cordata)

Stinkweed (Pluchea camphorata)

Water Smartweed (Polygonum amphibium)

Scarlet Smartweed (Polygonum amphibium var. coccineum)

Cespitose Knotweed (Polygonum cespitosum)

Mild Water Pepper (Polygonum hydropiperoides)

Pinkweed (Polygonum pensylvanicum)

Arrow-leaved Tear-thumb (Polygonum sagittatum)

Climbing False Buckwheat (Polygonum scandens)

Bristly Smartweed (Polygonum setaceum)

Mermaid Weed (Proserpinaca palustris)

Spearwort (Ranunculus laxicaulis)

Low Spearwort (Ranunculus pusillus)

Hooked Buttercup (Ranunculus recurvatus)

Celeryleaf Buttercup (Ranunculus sceleratus)

Sessile-flowered Cress (Rorippa sessiliflora)

Creeping Yellow-cress (Rorippa sylvestris)

Tall Coneflower (Rudbeckia laciniata)

Pale Dock (Rumex altissimus)

Curly Dock (Rumex crispus)

Great Water Dock (Rumex orbiculatus)

Swamp Dock (Rumex verticillatus)

Pennsylvania Saxifrage (Saxifraga pensylvanica)

Golden Ragwort (Senecio aureus)

Bur Cucumber (Sicyos angulatus)

Zigzag Goldenrod (Solidago flexicaulis)

Late Goldenrod (Solidago gigantea)

Roughleaf Goldenrod (Solidago patula)

Bog Goldenrod (Solidago uliginosa)

Prickly Sowthistle (Sonchus asper)

Yellow Ironweed (Verbesina alternifolia)

Ironweed (Vernonia missurica)

Cocklebur (Xanthium strumarium)