Saint James wort

Description:

Senecio jacobaea is categorised as a biennial plant. However, several studies have found it to demonstrate annual and perennial properties depending on environmental factors. In the first year of its biennial stage, Senecio jacobaea is in the rosette stage. It has dark green, basal leaves which are typically 5-20cm in length and 4-6cm in width with whitish, slightly hairy underside. The blunt toothed lobes of the leaves contribute to the ruffled appearance of the rosette. Seeds of outer florets are hairless and are normally 2mm long, while those from the inner florets have fine bristles up to 5mm in length. In the second year, flowering takes place with one or several stems, growing up to 1.2m. Leaves on the flowering stems are sessile, occurring in an alternating pattern. The flower head itself has a daisy-like appearance, consisting of disc florets as well as ray florets and is usually 2.5cm across in diameter. One of the more notable characteristics of the ray flowers is its 11-15 yellow petals, each being 5 – 10mm long. Senecio jacobaea has a fibrous taproot and is typically associated with a large rootstock

Habitat:

Senecio jacobaea invades disturbed sites including roadsides, pastures and forest clearings. Records show that the distribution of the species is unlikely to be affected by extreme weather, although some cases have noted that a decrease in its population may be correlated with dry summers. Additionally, Senecio jacobaea distribution may be influenced by soil moisture, but not by soil acidity or texture.

Notes:

Spotted in rural area of Deventer, Holland. (sources:see reference)