Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Saskatchewan, Montana, and Idaho; also from the central U.S. to eastern North America.
Habitat: Disturbed soils, waste lots, and cultivated areas.
Flowers: April-July
Origin: Introduced from Europe
Growth Duration: Annual
Conservation Status: Not of concern
Pollination: Self-pollination, generalist
Low, spreading annual, the stems prostrate to ascending, up to 15 cm. long.
Leaves opposite, attached to each other at the base, linear, with a stiff, sharp point, 5-15 mm. long.
Flowers very small, greenish, in a tight, dichotomously-branched inflorescence; calyx bell-shaped, 10-nerved, 3-4 mm. long, the 5 lobes narrowly lanceolate, equaling the tube; petals none; stamens 10, borne on a disk at the top of the calyx tube; styles 2.
Ovoid, 1-celled, 1-seeded utricle enclosed by the hardened calyx tube.
Publication: Sp. Pl. 1: 406. 1753.
- ssp. annuus – annual knawel Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to Saskatchewan, Montana, and Idaho; also from the central U.S. to eastern North America.
PNW Herbaria: Specimen records of Scleranthus annuus in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Scleranthus annuus checklist entry.
OregonFlora: Scleranthus annuus information.
E-Flora BC: Scleranthus annuus atlas page.
CalPhotos: Scleranthus annuus photos.
USDA Plants: Scleranthus annuus information.
