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Weed Identification

showy rattlebox



Scientific Name

Crotalaria spectabilis

Other Common Names:

showy crotalaria


Alternate, approximately 2 to 6 inches long, widest at the apex and tapering to the base. Leaves are without hairs on the upper surface and covered with appressed hairs on the lower surface. Leaves occur on short petioles. Stipules also occur at the base of the petioles but usually persist only for a short time.

Identifying Characteristics

A summer annual weed with relatively showy yellow flowers and distinctive seedpods. Leaves that are widest at the apex and taper to the base. Also the bright yellow flowers and distinctive seedpods help to distinguish this weed from most others.

Flower Seed Head

flowers occur on elongated inflorescences (racemes) and are stalked from a central axis, large, showy, and bright yellow in color. Flower stalks have a distinctive bract at their base that is approximately 7 to 12 mm long and 5 to 9 mm wide.

Seed Fruit

A legume that is 1 to 2 inches in length and takes on the appearance of an inflated cylindrical pod. Fruit turn brown to black when mature and the seed within the fruit often become unattached resulting in a rattlebox; sound when shaken.

Where Found

Showy crotalaria is primarily a weed of agronomic crops and may be found from Virginia to Missouri and southward.

Growth Habit

upright and nonwoody

Thorns or Spines

not present

Approximate Flower Diameter


Dominant Flower Color


Flower Symmetry

bilateral symmetry

Leaf Hairs

has hairs
no hairs

Leaf Shape


Leaf Arrangement


Leaf Margin


Leaf Structure


Leaf Stalk

shorter than leaf

Stem Hairs

no hairs

Stem Cross Section

round or oval

Milky Sap

not present

Root Structure


Life Cycle

summer annual


not present

Plant Type