- Types:
- show 46 types...
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Agrostemma githago, corn campion, corn cockle, crown-of-the-field
European annual having large trumpet-shaped reddish-purple flowers and poisonous seed; a common weed in grainfields and beside roadways; naturalized in America
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Scleranthus annuus, knawe, knawel
widely distributed low-growing Eurasian herb having narrow leaves and inconspicuous green flowers
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Spergula arvensis, corn spurrey, corn spurry
small European weed with whorled leaves and white flowers
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Spergularia rubra, sand spurry, sea spurry
prostrate weedy herb with tiny pink flowers; widespread throughout Europe and Asia on sand dunes and heath and coastal cliffs; naturalized in eastern North America
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Indian chickweed, Molluga verticillata, carpetweed
annual prostrate mat-forming weed having whorled leaves and small greenish-white flowers; widespread throughout North America
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Alternanthera philoxeroides, alligator grass, alligator weed
prolific South American aquatic weed having grasslike leaves and short spikes of white flowers; clogs waterways with dense floating masses
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Barbarea vulgaris, Sisymbrium barbarea, rockcress, rocket cress, yellow rocket
noxious cress with yellow flowers; sometimes placed in genus Sisymbrium
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Erysimum cheiranthoides, wormseed mustard
slender yellow-flowered European mustard often troublesome as a weed; formerly used as an anthelmintic
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Raphanus raphanistrum, jointed charlock, runch, wild radish, wild rape
Eurasian weed having yellow or mauve or white flowers and podlike fruits
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pennycress
any of several plants of the genus Thlaspi
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ambrosia, bitterweed, ragweed
any of numerous chiefly North American weedy plants constituting the genus Ambrosia that produce highly allergenic pollen responsible for much hay fever and asthma
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thistle
any of numerous plants of the family Compositae and especially of the genera Carduus and Cirsium and Onopordum having prickly-edged leaves
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Barnaby's thistle, Centaurea solstitialis, yellow star-thistle
European weed having a winged stem and hairy leaves; adventive in the eastern United States
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Canadian fleabane, Conyza canadensis, Erigeron canadensis, fleabane, horseweed
common North American weed with linear leaves and small discoid heads of yellowish flowers; widely naturalized throughout temperate regions; sometimes placed in genus Erigeron
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Erechtites hieracifolia, fireweed
an American weedy plant with small white or greenish flowers
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Hieracium praealtum, king devil, yellow hawkweed
European hawkweed introduced into northeastern United States; locally troublesome weeds
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California dandelion, Hypochaeris radicata, capeweed, cat's-ear, gosmore
European weed widely naturalized in North America having yellow flower heads and leaves resembling a cat's ears
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Parthenium hysterophorus, bastard feverfew
tropical American annual weed with small radiate heads of white flowers; adventive in southern United States
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Picris echioides, bitterweed, bristly oxtongue, bugloss, oxtongue
widespread European weed with spiny tongue-shaped leaves and yellow flowers; naturalized in United States
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Hieracium aurantiacum, Pilosella aurantiaca, orange hawkweed
European hawkweed having flower heads with bright orange-red rays; a troublesome weed especially as naturalized in northeastern North America; sometimes placed in genus Hieracium
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Senecio doublasii, threadleaf groundsel
bluish-green bushy leafy plant covered with close white wool and bearing branched clusters of yellow flower heads; southwestern United States; toxic to range livestock
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Senecio jacobaea, benweed, ragweed, ragwort, tansy ragwort
widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and toxic to cattle if consumed in quantity
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Senecio vulgaris, groundsel
Eurasian weed with heads of small yellow flowers
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cockle-bur, cockle-burr, cocklebur, cockleburr
any coarse weed of the genus Xanthium having spiny burrs
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nettle
any of numerous plants having stinging hairs that cause skin irritation on contact (especially of the genus Urtica or family Urticaceae)
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tumbleweed
any plant that breaks away from its roots in autumn and is driven by the wind as a light rolling mass
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madnep, wild parsnip
biennial weed in Europe and America having large pinnate leaves and yellow flowers and a bitter and somewhat poisonous root; the ancestor of cultivated parsnip
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French weed, Thlaspi arvense, fanweed, field pennycress, mithridate mustard, penny grass, stinkweed
foetid Eurasian weed having round flat pods; naturalized throughout North America
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Ambrosia artemisiifolia, common ragweed
annual weed with finely divided foliage and spikes of green flowers; common in North America; introduced elsewhere accidentally
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Ambrosia trifida, great ragweed
a coarse annual with some leaves deeply and palmately three-cleft or five-cleft
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Ambrosia psilostachya, perennial ragweed, western ragweed
coarse perennial ragweed with creeping roots of dry barren lands of southwestern United States and Mexico
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Carduus crispus, welted thistle
European biennial introduced in North America having flower heads in crowded clusters at ends of branches
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Carduus nutans, musk thistle, nodding thistle
Eurasian perennial naturalized in eastern North America having very spiny white cottony foliage and nodding musky crimson flower heads; valuable source of nectar
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carline thistle
a thistle of the genus Carlina
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plume thistle, plumed thistle
any of numerous biennial to perennial herbs with handsome purple or yellow or occasionally white flower heads
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Cirsium discolor, field thistle
stout North American thistle with purplish-pink flower heads
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Cirsium helenioides, Cirsium heterophylum, melancholy thistle
perennial stoloniferous thistle of northern Europe with lanceolate basal leaves and usually solitary heads of reddish-purple flowers
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Cnicus benedictus, blessed thistle, sweet sultan
annual of Mediterranean to Portugal having hairy stems and minutely spiny-toothed leaves and large heads of yellow flowers
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Onopordon acanthium, Onopordum acanthium, Scotch thistle, cotton thistle, woolly thistle
biennial Eurasian white hairy thistle having pale purple flowers; naturalized in North America
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golden thistle
any of several spiny Mediterranean herbs of the genus Scolymus having yellow flower heads
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Urtica dioica, stinging nettle
perennial Eurasian nettle established in North America having broad coarsely toothed leaves with copious stinging hairs
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Roman nettle, Urtica pipulifera
annual European nettle with stinging foliage and small clusters of green flowers
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Laportea canadensis, wood nettle
American perennial herb found in rich woods and provided with stinging hairs; provides fibers used for textiles
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Pilea pumilla, clearweed, dead nettle, richweed
a plants of the genus Pilea having drooping green flower clusters and smooth translucent stems and leaves
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Pilea microphylla, artillery plant
tropical American stingless nettle that discharges its pollen explosively
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Pilea involucrata, friendship plant, panamica, panamiga
low stingless nettle of Central and South America having velvety brownish-green toothed leaves and clusters of small green flowers
