Practical ecological knowledge for the temperate reader.

Senecio Sp. - Groundsel

Family: Asteraceae (Aster family) [E-flora]

"Annual to shrub, from taproot, rhizome, or button-like caudex. Stem: 1–many, simple or branched. Leaf: alternate; mostly basal to evenly distributed; proximal generally ± petioled; middle generally reduced, sessile, often clasping. Inflorescence: heads radiate, disciform, or discoid, generally in cyme-like clusters; involucre cylindric to urn- or bell-shaped, main phyllaries generally 8, 13, or 21 in 1 series, subtended by few to many, generally much-reduced outer phyllaries, reflexed in fruit, green, often black-tipped, linear to narrowly lanceolate, glabrous or hairy; receptacle epaleate. Ray flower: 0–21; ray generally yellow (white, pink-purple), occasionally much-reduced and scarcely exceeding phyllaries. Disk flower: 3–100+; corolla tubular to bell-shaped, lobes erect to recurved, pale to deep yellow; anther tip ± triangular-ovate; style branch tips obtuse or truncate. Fruit: cylindric, generally shallow-ribbed or -angled, glabrous or stiff-hairy; pappus of minutely barbed bristles, white to tan.
1000+ species: worldwide, especially abundant in warm temperate, subtropical and tropical areas at mid to upper elevations. (Latin: old man, from white pappus) [Barkley 2006 FNANM 20:544–570] Many North American species formerly treated as Senecio now in Packera. The common names groundsel, ragwort, and butterweed apply to species of both genera." [Jepson]

Local Species;

  1. Senecio jacobaea - tansy ragwort [E-flora]
  2. Senecio pseudoarnica - beach groundsel (Haida Gwaii) [E-flora]
  3. Senecio sylvaticus - wood groundsel [E-flora]
  4. Senecio triangularis - arrow-leaved groundsel [E-flora]
  5. Senecio viscosus - sticky ragwort [E-flora]
  6. Senecio vulgaris - common groundsel [E-flora]

Senecio jacobaea - Tansy ragwort


"Tansy ragwort is an invasive introduced species from Europe that is now found in eastern and western North America, but is absent from the prairies and midwestern states...Biological control methods have been applied to it, including the introduction of the cinnabar moth (tiger moth) (Tyria jacobaeae) to North America, a species which feeds exclusively on tansy ragwort. In our region, tansy ragwort can be confused with common tansy (Tanacetum vulgare), however, tansy ragwort has yellow ray petals, while common tansy lacks ray petals."[IFBC-E-flora-1]

Additional Notes

"Tansy ragwort is considered an emerging invasive species in the Vancouver region by the Greater Vancouver Invasive Plant Council (2009). ...It is listed as one of the top fourteen species of concern by the Coastal Invasive Plant Council."[IFBC-E-flora-1]

Senecio pseudoarnica - Beach groundsel (seaside ragwort)

Senecio sylvaticus - Wood groundsel

Senecio triangularis - Arrow-leaved groundsel

Senecio viscosus - Sticky ragwort

Senecio vulgaris - Common groundsel


"Most ragworts should be considered potentially poisonous..." [CPPM]

Edible Uses

Other Uses

Medicinal Uses

S. vulgaris; Groundsel has a long history of herbal use and, although not an official plant, it is still often used by herbalists.[4] [PFAF]

Further Medicinal Usage





Other Senecio Sp.

"There are 2,000 to 3,000 species of Senecio, many of which contain a toxic concentration of pyrrolizidine alkaloids." [HPIP Shih] "Rubiolo et al. [81] evaluated the mutagenicity of a series of pyrrolizidine alkaloids and extracts of several Italian Senecio species containing pyrrolizidine alkaloids including Senecio inaeguidens, S. fuchii, and S. cacaliastes." [ModPhyt] "All 1500 species of the mega-genus are believed to contain them, including the common ragwort (S. jacobeae) (Harborne and Baxter 1993)." [Pengelly TCMP]

A brief look at a few random species of the genera Senecio;


Page last modified on Saturday, July 1, 2023 5:13 PM