Sp. Pl. 1: 307. 1753.
Plants (10–) 20–30 (–40) cm; bulbs renewed each year, 1–2 × 1–2.5 (–3.5) cm; bulblets numerous. Leaves 4–6 (–9); blade with white adaxial stripe, 20–30 cm × 3–5 (–8) mm. Scape 1–3 dm. Inflorescences corymbose, (4–) 8–20-flowered, flat-topped; bracts to 4 cm. Flowers erect; perianth opening flat or bowl-shaped in sun, closing at night, remaining closed on cloudy days; tepals white with wide green abaxial stripe, lanceolate to oblong-lanceolate, 15–22 (–30) × 7–8 mm; stamens: outer 5–7 × 2–3 mm, inner 6–8 × 2–3 mm; filaments simple, flattened; anthers 2–4 mm; ovary ovoid to obovoid, strongly 6-angled, 5–6 mm; style 3–4 mm; lower pedicels 2–6 cm. Capsules oblong-ovoid. 2n = 18, 20, 27, 28, 35, 36, 42, 44, 45, 54, 72, 90, 108.
Phenology: Flowering spring.
Habitat: Roadsides, open forests, waste places, dumps
Elevation: 0–1500 m
Introduced; B.C., N.B., Nfld. and Labr. (Nfld.), N.S., Ont., Que., Ala., Ark., Conn., Del., D.C., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Europe, n Africa, Asia, Middle East, expected elsewhere
Planted as a garden ornamental, Ornithogalum umbellatum produces many offsetting bulblets that are transported in soil and can become rampant weeds. Adding to the vegetative vigor of this species may be its aneuploid-polyploid karyology (T. W. J. Gadella and L. van Raamsdonk 1981; L. van Raamsdonk 1984). The flowers are noteworthy for their regularity in opening just before noon and closing again before sunset.
Two digitalis-like glycosides, convallatoxin and convalloside, poisonous to humans and livestock, are found throughout the plant, but are concentrated in the bulbs and the flowers (W. H. Blackwell 1990; K. F. Lampe and M. A. McCann 1985; D. G. Spoerke Jr. and S. C. Smolinske 1990).
"dm" is not declared as a valid unit of measurement for this property."thicker" is not a number.