Photo from Weeds of Nebraska and the Great Plains
Toxicity: Horses, even when cured in hay.
Growth Habit: Annual forb that grows 1 to 2.6 feet in height.
Leaves: Alternate; blades simple, oblanceolate to occasionally elliptic, tip sharply pointed to blunt or rounded, margins entire, grayish-green, stellate (star-shaped) pubescence.
Stem: Stiffly erect, usually branching above, grayish-green, stellate (star shaped) pubescence)
Flower: White, petals 4, deeply divided, short filaments flanked on each side by a short semicircular gland; sepals 4, equal ascending.
Seeds: Round to oblong, narrowly winged, grayish-brown, and rough
Habitat: Hoary Alyssum can be found in pastures, small grain fields, roadsides, & waste areas.
Caution: Hoary Alyssum is toxic to horses.