Senecio

• threadleaf groundsel

  Bluish-green bushy leafy plant covered with close white wool and bearing branched...

• ragweed

  Widespread European weed having yellow daisylike flowers; sometimes an obnoxious weed and...

• groundsel

  Eurasian weed with heads of small yellow flowers.

Also contains

• thistle

  Any of numerous plants of the family Compositae and especially of the genera Carduus and...

• nettle

  Any of numerous plants having stinging hairs that cause skin irritation on contact (especially...

• ambrosia

  Any of numerous chiefly North American weedy plants constituting the genus Ambrosia that...

• pennycress

  Any of several plants of the genus Thlaspi.

• fireweed

  An American weedy plant with small white or greenish flowers.

• wormseed mustard

  Slender yellow-flowered European mustard often troublesome as a weed; formerly...

• jointed charlock

  Eurasian weed having yellow or mauve or white flowers and podlike fruits.

• knawel

  Widely distributed low-growing Eurasian herb having narrow leaves and inconspicuous green...

• bastard feverfew

  Tropical American annual weed with small radiate heads of white flowers; adventive...

• Barnaby's thistle

  European weed having a winged stem and hairy leaves; adventive in the eastern...

• corn spurry

  Small European weed with whorled leaves and white flowers.

• wild parsnip

  Biennial weed in Europe and America having large pinnate leaves and yellow flowers...

• sand spurry

  Prostrate weedy herb with tiny pink flowers; widespread throughout Europe and Asia on...

• bitterweed

  Widespread European weed with spiny tongue-shaped leaves and yellow flowers; naturalized...

• rockcress

  Noxious cress with yellow flowers; sometimes placed in genus Sisymbrium.

• orange hawkweed

  European hawkweed having flower heads with bright orange-red rays; a troublesome...

• cocklebur

  Any coarse weed of the genus Xanthium having spiny burrs.

• carpetweed

  Annual prostrate mat-forming weed having whorled leaves and small greenish-white flowers;...

• king devil

  European hawkweed introduced into northeastern United States; locally troublesome we...

• horseweed

  Common North American weed with linear leaves and small discoid heads of yellowish flowers;...

• alligator weed

  Prolific South American aquatic weed having grasslike leaves and short spikes of...

• tumbleweed

  Any plant that breaks away from its roots in autumn and is driven by the wind as a light...

• cat's-ear

  European weed widely naturalized in North America having yellow flower heads and leaves...

• corn cockle

  European annual having large trumpet-shaped reddish-purple flowers and poisonous seed;...