Canada thistle (Cirsium arvense L.)

Family: Asteraceae Dumort 
Stems ramified, spineless, nearly hairless, angularly furrowed, up to 40 - 160 cm.
Leaves first leaves inverse-ovate, following leaves lanceolate, simple to pinnatifid, wavy-ruffled, sessile.
Root system vertical.
Flowering in june—september.
Inflorescence — rose flowers.
Fruit one-seeded indehiscent fruit, 1.7-3.9 mm (0.067 - 0.15 inch) oblong, slightly crooked, yellow-gray to olive-green, pappus up to 20 mm (0.78 inch) long.
Reproducing ability - up to 40 thousands seed on one plant. There is no information about seeds in soil
To germinate at a temperature of 4-40° C.
Germination in spring , march - april.
Widespreaded everywhere.
Clog seeds of spring and winter grains and vegetable crops. To grows in gardens, no tillage lands.