Note: Some species are placed in multiple categories when colors and/or shapes are subjective or ambiguous.
Pink or Red
Three petals
Asarum canadense
Murdannia keisak
Trillium sessile
Four petals
Galium pilosum
Oenothera speciosa
Five petals
Agalinis purpurea
Aquilegia canadensis
Asclepias incarnata
Asclepias purpurascens
Asclepias syriaca
Campsis radicans
Claytonia virginica
Dianthus armeria
Elephantopus carolinianus
Erodium cicutarium
Geranium carolinianum
Geranium dissectum
Geranium maculatum
Geranium molle
Geranium pusillum
Gypsophila muralis
Malva neglecta
Oxalis violacea
Persicaria hydropiperoides
Persicaria sagittata
Phlox divaricata
Phlox paniculata
Primula meadia
Sabatia angularis
Six petals
Allium canadense
Allium vineale
Lythrum salicaria
Many petals
Carduus acanthoides
Carduus nutans
Centaurea stoebe
Cirsium arvense
Cirsium discolor
Cirsium vulgare
Elephantopus carolinianus
Pea-shaped petals
Desmodium glabellum
Kummerowia stipulacea
Kummerowia striata
Lathyrus latifolius
Lespedeza virginica
Securigera varia
Strophostyles umbellata
Vicia sativa
Vicia villosa
Irregular
Allium vineale
Campsis radicans
Carduus nutans
Cirsium arvense
Cirsium vulgare
Clinopodium vulgare
Cypripedium acaule
Desmodium glabellum
Lamium amplexicaule
Lamium purpureum
Leonurus cardiaca
Liatris squarrosa
Lobelia cardinalis
Lonicera sempervirens
Mazus pumilus
Monarda didyma
Monarda fistulosa
Perilla frutescens
Persicaria longiseta
Persicaria pensylvanica
Physostegia virginiana
Polygala sanguinea
Securigera varia
Teucrium canadense
Trifolium arvense
Trifolium pratense
Blue or Purple
Three petals
Commelina communis
Tradescantia virginiana
Four petals
Cardamine douglassii
Clematis ochroleuca
Hesperis matronalis
Houstonia caerulea
Houstonia longifolia
Houstonia purpurea
Justicia americana
Mentha arvensis
Pycnanthemum tenuifolium
Sherardia arvensis
Veronica arvensis
Veronica hederifolia
Veronica officinalis
Veronica persica
Veronica serpyllifolia
Five petals
Asclepias purpurascens
Cymbalaria muralis
Cynoglossum virginianum
Delphinium tricorne
Echium vulgare
Ipomoea hederacea
Liatris spicata
Mertensia virginica
Mimulus alatus
Mimulus ringens
Orobanche uniflora
Phacelia dubia
Phlox divaricata
Ruellia caroliniensis
Solanum dulcamara
Triodanis perfoliata
Vinca minor
Viola bicolor
Viola pedata
Viola sagittata
Viola sororia
Six petals
Iris versicolor
Lythrum salicaria
Pontederia cordata
Sisyrinchium angustifolium
Many petals
Centaurea cyanus
Cichorium intybus
Conoclinium coelestinum
Echinacea purpurea
Lactuca floridiana
Symphyotrichum novae-angliae
Symphyotrichum patens
Symphyotrichum puniceum
Pea-shaped petals
Desmodium nudiflorum
Vicia villosa
Irregular
Cymbalaria muralis
Dipsacus fullonum
Glechoma hederacea
Justicia americana
Lindernia dubia
Lobelia inflata
Monarda fistulosa
Prunella vulgaris
Pycnanthemum incanum
Pycnanthemum muticum
Salvia lyrata
Scutellaria elliptica
Scutellaria incana
Symplocarpus foetidus
Trichostema dichotomum
White
Three petals
Four petals
Alliaria petiolata
Arabidopsis lyrata
Boechera laevigata
Capsella bursa-pastoris
Cardamine bulbosa
Cardamine concatenata
Cardamine douglassii
Cardamine hirsuta
Clematis terniflora
Clematis virginiana
Dicentra canadensis
Dicentra cucullaria
Diodia virginiana
Draba verna
Euphorbia maculata
Galium aparine
Galium asprellum
Galium concinnum
Justicia americana
Lepidium virginicum
Lycopus americanus
Mitchella repens
Obolaria virginica
Persicaria virginiana
Pycnanthemum tenuifolium
Sedum ternatum
Five petals
Achillea millefolium
Aegopodium podagraria
Apocynum androsaemifolium
Apocynum cannabinum
Arenaria serpyllifolia
Asclepias verticillata
Buglossoides arvensis
Calystegia sepium
Cerastium arvense
Cerastium fontanum
Cerastium glomeratum
Chaerophyllum tainturieri
Comandra umbellata
Conium maculatum
Cryptotaenia canadensis
Daucus carota
Ellisia nyctelea
Epigaea repens
Erigenia bulbosa
Euphorbia corollata
Fragaria virginiana
Geum canadense
Hydrophyllum canadense
Hydrophyllum virginianum
Ipomoea lacunosa
Ipomoea pandurata
Micranthes virginiensis
Monotropa uniflora
Myosotis verna
Osmorhiza longistylis
Persicaria hydropiperoides
Persicaria sagittata
Phlox divaricata
Phlox subulata
Phytolacca americana
Rubus flagellaris
Silene latifolia
Solanum carolinense
Solanum ptychanthum
Stellaria longifolia
Stellaria media
Stellaria pubera
Valerianella radiata
Verbascum blattaria
Verbena urticifolia
Viola canadensis
Viola striata
Six petals
Allium canadense
Erythronium albidum
Maianthemum racemosum
Ornithogalum nutans
Ornithogalum umbellatum
Podophyllum peltatum
Many petals
Ageratina altissima
Anthemis arvensis
Eclipta prostata
Erigeron annuus
Erigeron philadelphicus
Eupatorium altissimum
Eupatorium hyssopifolium
Eupatorium perfoliatum
Eupatorium serotinum
Eurybia divaricata
Jeffersonia diphylla
Leucanthemum vulgare
Nymphaea odorata
Podophyllum peltatum
Sanguinaria canadensis
Sericocarpus asteroides
Symphyotrichum lanceolatum
Symphyotrichum lateriflorum
Symphyotrichum racemosum
Thalictrum pubescens
Thalictrum thalictroides
Pea-shaped petals
Lespedeza cuneata
Melilotus albus
Irregular
Antennaria neglecta
Antennaria parlinii
Antennaria plantaginifolia
Arnoglossum atriplicifolium
Dicentra canadensis
Dicentra cucullaria
Dipsacus laciniatus
Erechtites hieraciifolius
Justicia americana
Lobelia inflata
Lonicera japonica
Mikania scandens
Monotropa uniflora
Nepeta cataria
Persicaria punctata
Platanthera lacera
Pseudognaphalium obtusifolium
Pycnanthemum incanum
Pycnanthemum muticum
Saururus cernuus
Spiranthes lacera
Trifolium repens
Yellow or Orange
Four petals
Barbarea vulgaris
Brassica rapa
Chelidonium majus
Clematis ochroleuca
Cruciata pedemontana
Hypericum hypericoides
Ludwigia alternifolia
Oenothera biennis
Oenothera pilosella
Five petals
Abutilon theophrasti
Agrimonia parviflora
Anagallis arvensis
Asclepias tuberosa
Chrysogonum virginianum
Duchesnea indica
Hypericum mutilum
Hypericum perforatum
Hypericum punctatum
Ludwigia peploides
Lysimachia ciliata
Lysimachia quadrifolia
Portulaca oleracea
Potentilla canadensis
Potentilla norvegica
Potentilla recta
Potentilla simplex
Sedum sarmentosum
Verbascum blattaria
Verbascum thapsus
Viola pubescens
Six petals
Caulophyllum thalictroides
Erythronium americanum
Hypoxis hirsuta
Iris pseudacorus
Uvularia perfoliata
Many petals
Bidens aristosa
Coreopsis tinctora
Coreopsis verticillata
Euthamia graminifolia
Ficaria verna
Helenium autumnale
Helenium flexuosum
Helianthus decapetalus
Helianthus divaricatus
Helianthus laetiflorus
Helianthus tuberosus
Heliopsis helianthoides
Hieracium gronovii
Hieracium paniculatum
Krigia dandelion
Lactuca saligna
Lactuca serriola
Packera anonyma
Packera aurea
Pilosella caespitosa
Ratibida pinnata
Rudbeckia fulgida
Rudbeckia hirta
Rudbeckia lacinata
Rudbeckia triloba
Silphium asteriscus
Solidago rigida
Sonchus asper
Taraxacum officinale
Youngia japonica
Pea-shaped petals
Lotus corniculatus
Medicago lupulina
Melilotus officinalis
Stylosanthes biflora
Irregular
Bidens bipinnata
Bidens frondosa
Corydalis flavula
Cypripedium parviflorum
Impatiens capensis
Lonicera japonica
Monarda punctata
Pedicularis canadensis
Pseudognaphalium obtusifolium
Senecio vulgaris
Green or Brown
Three petals
Five petals
Irregular
Ambrosia artemisiifolia
Ambrosia trifida
Arisaema triphyllum
Conopholis americana
Erechtites hieraciifolius
Pedicularis canadensis
Platanthera lacera
Rumex crispus
Saururus cernuus
Symplocarpus foetidus
