Annual, winter annual, or sometimes biennial.
The mature plant grows to about 0.6 m. Foliage consists of irregularly
toothed, dandelion-shaped leaves. Yellow disk flowers with no ray petals
are numerous and the floral bracts
are black-tipped. Young leaves are purple underneath.
Common groundsel is a problem weed in cultivated crops, gardens,
and nurseries. It is poisonous to cattle and horses and toxic to humans.
It contains pyrrolizidine alkaloids, which can cause irreversible liver
damage and possibly death.
Common groundsel grows mainly in cultivated soil, but may be found
in pastures or along roadsides and disturbed areas. It is best adapted
to wet environments and nutrient rich soils. It is common in west-central
and southwestern British Columbia, but rare elsewhere in the province,
although it is present in all agricultural regions.
Seeds have white hairs and are easily dispersed by wind. Seeds may mature
in opened flowers even after the plants have been killed.