BugwoodWiki Article

tansy ragwort
Senecio jacobaea L.

Overview

Appearance
Senecio jacobaea is a biennial to short lived perennial herb native to Eurasia. Plants can reach 1-4 ft. (0.3-1.2 m) tall.
Foliage
The leaves of the basal rosette have petioles, cauline (stem) leaves are sessile and both are deeply lobed and alternate. The leaf lobes are oblong and web-shaped. The margins of the leaves are dentate. The leaves can measure between 1.5-8 in. (4-20 cm) long and 0.75-2.25 in. (2-6 cm) wide. The leaf is medium green above, lighter underneath and occasionally tomentose.
Flowers
Flowering occurs in summer to early fall, when numerous yellow, daisy-like flowers develop in a flat topped inflorescence at the apex of the stems. Flower heads are 0.8 in. (2 cm) in diameter.
Fruit
Fruit are small and have a persistent ring of white hairs (pappus) attached. 60,000-70,000 seeds produced per plant. Seeds can remain viable for up to 15 years.
Ecological Threat
S. jacobaea invades rangelands in the West where it is toxic to livestock. In the East it invades pastures, open forests, swamps, riverbeds, coastal grasslands and disturbed areas. It was first reported in the United States in the early 1900’s. It is native to most of Europe, North Africa and western Asia and may have been introduced into the United States as a medicinal plant.

Resources

Image Sets
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Maps


EDDMapS Distribution - This map is incomplete and is based only on current site and county level reports made by experts, herbaria, and literature. For more information, visit www.eddmaps.org

EDDMapS Distribution

State Invasive List - This map identifies those states that list this species on their invasive species list. For more information, visit Invasive.org

State Invasives List

Taxonomic Rank

Kingdom: Plantae
Phylum: Magnoliophyta
Class: Magnoliopsida
Subclass: Asteridae
Order: Asterales
Family: Asteraceae
Genus: Senecio

Other System Links

Plants: SEJA
Bayer: SENJA
GRIN: 104534
ITIS: 36089
NPDN Pest: PBFCXBC

Synonyms and Other Names

Other Common Names:
ragwort, stinking Willie

Categories

Category: Forbs/Herbs