Crotalaria sagittalis (Rattlebox)

Plant Info
Also known as: Arrowhead Rattle-box
Family:Fabaceae (Pea)
Life cycle:annual
  • State Special Concern
Habitat:sun; dry, sandy or gravelly soil; prairies, along railroads,
Bloom season:June - September
Plant height:4 to 16 inches
Wetland Indicator Status:none
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: irregular Cluster type: raceme

[photo of flower] Racemes of 1 to 4 pea-shaped flowers on branching stems in the upper plant, alternating with and opposite to the leaves. Flowers are about 1/3 inch long, yellow, with a broad, nearly round erect petal at the top (the standard) that is barely notched at the tip, and 2 shorter lateral petals extending out over the green keel. The calyx holding the flower is short-stalked, 5-pronged, the prongs as long as or longer than the petals, and covered in long white hairs. Only a few flowers may be open at a time.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

[photo of leaves] Leaves are 1 to 3 inches long, to 2/3 inch wide, lance to elliptic, toothless, covered in long white hairs on both surfaces, rounded to pointed at the tip, stalkless or short-stalked. Stems are erect and branching, densely hairy, green to purplish. Where the raceme stalk meets the stem is a joined pair of leafy appendages (stipule) about ½ inch long, extending down the stem and each side 1-pronged at the tip.

Fruit: Fruit type: capsule/pod

[photo of fruit] Fruit is an inflated, oblong pod to 1¼ inch long at maturity, initially light green, ripening to purplish black.


Rattlebox is not commonly encountered, only present in a few Minnesota counties as we are on the northern fringe of its natural range. It is listed as a Special Concern species in Wisconsin and was designated as such in Minnesota in 2013 due to its low populations and the dwindling prairie and savanna habitats this species calls home.

Native Plant Nurseries, Restoration and Landscaping Services ↓

Map of native plant resources in the upper midwest

  • ReWild Native Gardens
  • Out Back Nursery
  • Shop for native seeds and plants at!
  • Shooting Star Native Seeds - Native Prairie Grass and Wildflower Seeds
  • Morning Sky Greenery - Native Prairie Plants

More photos

Photos by K. Chayka taken at Whitewater WMA, Winona County. Photos courtesy Peter M. Dziuk taken in Winona County and in a private garden in Anoka County.


Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Stephanie Badavinac - Bovey, MN -Lawrence Lake
on: 2021-08-10 10:19:45

I found a few of these plants growing in our field this summer, and I have never noticed them before. I am not 100% sure on the identification, but this is the closest I have found so far. I have a couple photos I took-the plants are tall, and appears the deer like the taste of the flowers as well.

Posted by: K. Chayka
on: 2021-08-10 10:36:31

Stephanie, if you look at the distribution map, you'll see the range of this species doesn't extend that far north. It is also pretty short so a tall plant would be atypical. You must have found something else. If you'd like confirmation on the ID, post your images on the Minnesota Wildflowers Facebook page.

Post a comment

Note: All comments are moderated before posting to keep the riff-raff out. An email address is required, but will not be posted—it will only be used for information exchange between the 2 of us (if needed) and will never be given to a 3rd party without your express permission.

For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.


Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because Id like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.