groundsel

noun

1. any composite plant of the genus Senecio, especially S. vulgaris, a common weed having clusters of small yellow disk flowers without rays.

noun

1. groundsill.

noun

1. any of certain plants of the genus Senecio, esp S. vulgaris, a Eurasian weed with heads of small yellow flowers: family Asteraceae (composites)See also ragwort
2. groundsel tree a shrub, Baccharis halimifolia, of E North America, with white plumelike fruits: family Asteraceae