Tall Wormseed Wallflower
- Name also: European Wallflower, Siberian Wallflower
- Latin synonym: Erysimum virgatum, Erysimum hieraciifolium
- Family: Mustard Family – Brassicaceae (Cruciferae)
- Growing form: Biennial herb.
- Height: 50–100 cm (20–40 in.). Stem unbranched–sparsely branched, bristly, roughly haired.
- Flower: Corolla regular (actinomorphic), brilliant yellow, approx. 1–1.5 cm (0.4–0.6 in.) wide; petals four, 8–10(–12) mm (0.32–0.4(–0.48 in.) long. Sepals 4. Stamens 6, of which 2 short and 4 long. Gynoecium fused, a single carpel. Inflorescence a raceme, extending in fruiting stage.
- Leaves: Alternate, stem leaves almost stalkless. Blade narrowly lanceolate, stellate-haired, sparsely shallow-toothed.
- Fruit: Many-seeded, 4-edged, stellate-haired, 3–5 cm (1.2–2 in.) long, parallel to stem siliqua, tipped with approx. 2 mm (0.08 in.) long bristle. Stalk approx. 5 mm (0.2 in.), ascending oblique.
- Habitat: Gravelly and stony sea-shores, sea-shore meadows and hedgerows, also dry stream-bank meadows, fell slopes, sometimes waste ground, banks, embankments.
- Flowering time: June–July.
Tall wormseed wallflower is an original northern plant in Finland, and it has spread to the south along the coast during the warm period that followed the Ice Age. It usually grows alone or in small groups along rocky coasts and stony and dry coastal meadows. In northern Finland it grows rarely on lower fell slopes and slightly more commonly in the forest belt at the foot of precipices and on gravels and riverside meadows. However, it has never established a foothold on the shores of Finland’s thousands of lakes.
People browsing these pages might notice that members of the Mustard family seem to be completely dependent on man-made environments. Tall wormseed wallflower is a rare species within its family that can be found far from humans: while at least inland in southern Finland several stands are a result of people’s actions, the plant has also travelled along railways as far north as the Kemi region.
Tall wormseed wallflower can be differentiated from its close relative treacle mustard (E. cheiranthoides) on account of its large flowers, tooth-margined leaves and especially its shorter and more erect fruit-stalks.