Annual or short-lived perennial herb 20 - 50 cm tall Leaves: alternate, stalkless, hairy, 3 - 7 cm long, about 2 cm wide, oblong or elongate spoon-shaped, widest past middle, tapering toward base, and usually with blunt or rounded tips. Inflorescence: terminal, up to 10 cm long, one-sided, bractless, appressed-hairy, spike-like branches with coiled tips, and many, well spaced, stalked flowers. Flowers: stalked, blue with yellow centers, small (0.5 - 0.8 cm broad), radially symmetric, somewhat funnel-shaped with well-developed tube and shorter, flat spreading, rounded lobes. The ascending or spreading flower stalks are usually longer than the sepals (4 - 5 mm), and elongate up to 1 cm in fruit. Sepals: five, but fused for about one-third their length, then separating into five, somewhat spreading, linear to narrowly triangular lobes which are much longer than the fused base. The calyx as a whole is 4 - 5 mm long, and rough with a dense covering of stiff hooked hairs. Petals: five, but fused for over half their length into a relatively narrow tube, then separating into five, rounded, spreading lobes, which form a flat surface. At the base of the spreading petal lobes, the throat of the petal tube is blocked by five small projections or appendages (fornices). Stamens: five, attached to inside of petal tube by short filaments, the anthers not extending past the petal tube. Pistil: with one, deeply four-lobed, superior ovary; one, short, inconspicuous style; and one, unlobed stigma. Fruit: a cluster of four, fairly erect, shiny, greenish black to black, 1.5 - 2 mm long, under 1.5 mm wide, compressed or somewhat flattened lengthwise, somewhat egg-shaped nutlets with pointed tips and a prominent lateral ridge running around the edge of the flattened faces. The nutlet clusters are enclosed by the slightly spreading or outward curved sepal lobes, and held on erect or spreading, up to 0.9 cm long stalks. Stems: erect, tufted, often much branched, and bristly-hairy.
Similar species: Myosotis sylvatica is often confused with M. arvensis, except that species has smaller flowers (normally under 4 mm wide), the petal lobes are curved upward creating a cup-like shape instead of being flat, and the sepal lobes tend to be erect or closed around the nutlets in fruit. Other species of Myosotis in the Chicago Region either have shorter flower stalks, flowers with non-spreading petal lobes, or they lack any hooked hairs in the inflorescence.
Flowering: June to July
Habitat and ecology: Native to Eurasia, commonly cultivated, but rarely escaping.
Short-lived perennial to 5 dm; lvs oblong to lanceolate or spatulate, the larger 3-7 cm; racemes naked, seldom over 1 dm; fruiting pedicels 5-15 mm apart, ascending or spreading, to 9 mm; mature cal 4-5 mm, densely pubescent with hooked hairs, the lobes much longer than the tube; cor blue (white), salverform, the limb 5-8 mm wide; nutlets 1.5-2 mm; 2n=14-48. Native of Eurasia, occasionally escaped from cult. in our range. Apr.-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.