Knautia arvensis (L.) J.M. Coult.
Scabiosa arvensis L.
Field scabious, blue buttons
Field scabious is native throughout Europe. It has become naturalized in North America, after escaping from gardens, becoming overly common to invasive in some midwestern states. It is found along river banks and roadsides, and in meadows, pastures, waste ground, and well-lit forests.
Plants: 12-31" (30-80 cm) tall. Stems branch near the top, and are densely hairy and green to purplish, often with purple spots.
Leaves: Opposite, on short petioles or none at all, lanceloate-elliptic, gray-green, with soft hairs. The lowest leaves are up to 1" (3 cm) long. Stem leaves are pinnately divided, with a large terminal leaflet.
Flowers: Single flowers atop long stems are irregular, blue-violet, flattish or rounded, 1-1½" (2.5-3.8 cm) around. Each flower contains 85-100 florets. Florets near the center are funnel-shaped, with four lobes. Edge florets are larger and more irregular. Four violet-tipped stamens appear near the center of each flower. There are 8-12 sepals at the base of each flower. The calyx beneath the flower is small. Flowers appear June-August.
Fruits: A nutlet ~³/₁₆" (5-6 mm) × ¹/₁₆" (2 mm), thickly covered in hairs. A single plant produces up to 2000 seeds.
Medical: Flowers and stems are said to have an astringent, antiseptic, expectorant or purgative effect. None of these effects have been proven.
Knautia arvensis on www.luontoportti.com
Knautia arvensis at Minnesota Wildflowers
Knautia arvensis on Wikipedia
Knautia arvensis on the New England Wildflower Society’s GoBotany site
Knautia arvensis on Wikispecies
Knautia arvensis description by Thomas H. Kent, last updated 25 May 2020.