Groundsel, Common, Senecio vulgaris L.

Life Cycle

Annual.

Propagation

Reproducing by seed.

Stems

Stems erect or somewhat reclining, often branched, 10-60cm high, smooth, somewhat fleshy.

Leaves

Leaves alternate (1 per node), slightly fleshy, variable in shape from smooth and almost without teeth to shallowly or deeply lobed, with the lobes finely to coarsely and irregularly toothed; lower leaves stalked, upper ones stalkless and often clasping the stem.

Flowers and Fruit

Flower heads stalked in clusters at the end of stems and branches; each flower head 5-10mm across, cylindrical or conic, without ray florets; disk florets yellowish; involucral bracts (surrounding each flower head) small, overlapping, usually with distinct black tips; seeds small, short-hairy, with a prominent, white, hairy pappus. Flowers from June to late autumn.

Habitat

Common groundsel occurs throughout Ontario, often very abundantly, in gardens, row crops, waste places and roadsides.

Distinguishing Features

Young plants can be distinguished by their irregularly lobed and toothed leaves without white milky juice; older plants by their small conic-cylindrical flower heads with black-tipped involucral bracts around the base of each head.


Figure #1.

Mature plant


Figure #2.

Cotyledon


Figure #3.

Mature leaf


Figure #4.

Mature plant with flowering and mature fruit


Figure #5.

Yellow flower head with involucral bracts with the distinctive black tips


Figure #6.

Seed head with white hairy pappus