Crotalaria sagittalis Stephen M. Young

Crotalaria sagittalis
Stephen M. Young

Class
Dicotyledoneae (Dicots)
Family
Fabaceae (Pea Family)
State Protection
Endangered
Federal Protection
Not Listed
State Conservation Status Rank
S1
Global Conservation Status Rank
G5

Summary

Did you know?

The common name rattlebox comes from the genus name, which is derived from the Greek word "crotalon" meaning rattle (the genus for rattlesnake is Crotalus). When the fruits mature they become hardened and the seeds rattle around inside. The species is widespread in eastern United States and can be weedy. It is on the list of noxious weeds for Arkansas and even though there is plenty of weedy habitat in New York we are the northeastern edge of its range and there is some environmental factor limiting its spread.

State Ranking Justification

Two large populations exist along with one small population. All are threatened by succession or habitat destruction. About 15 historical records exist but none have been relocated.

Short-term Trends

Five populations have been found since the 1980s but two of these have been lost to habitat destruction or succession. The other three populations seem stable.

Long-term Trends

The long-term trend has declined over the past 100 years even though this plant was never very common in the state. There were about 15 historical localities from the early 20th century and none have been relocated. About half of these could be considered extirpated.

Conservation and Management

Threats

This species thrives in low nutrient disturbed areas and there is a natural threat from succession by other plants that can outcompete it if the areas are not kept open. Habitat destruction is also a threat when these open areas are converted to more permanent structures.

Conservation Strategies and Management Practices

The open habitat needs to be maintained while avoiding the direct destruction of plants.

Research Needs

Rattlebox grows in open natural or human disturbed areas which are plentiful throughout the state but it is unknown why it prefers only a small part of that habitat. Research is needed to understand this habitat preference. We need to know if this plant persists as a seed bank and if populations can be augmented by specific management practices.

Habitat

Habitat

Rattlebox is a weedy species, known in New York from a a variety of open disturbed sites with sandy soils, including pine plantations, pastures, and mowed fields. At these sites it is associated with little blue-stem (Schicachyrium scoparium), other grasses, and a diversity of weedy species (New York Natural Heritage Program 2007). Dry sandy or gravelly soil (Fernald 1970). Dry open soil and waste land, usually as a weed in our range and probably only introduced except along our southern border (Gleason & Cronquist 1991).

Associated Ecological Communities

  • Construction/road maintenance spoils
  • Mowed roadside/pathway
  • Pastureland
  • Pine plantation
  • Railroad*

Associated Species

  • Anthoxanthum odoratum (sweet vernal grass)
  • Cladonia
  • Danthonia spicata (poverty grass)
  • Desmodium
  • Festuca rubra
  • Panicum
  • Poa pratensis
  • Polytrichum
  • Rumex acetosella
  • Schizachyrium scoparium

Range

New York State Distribution

In New York this species is found in the Lower Hudson Valley and Long Island, ranging as far north as Orange County.

Global Distribution

This weedy species is found from New Hampshire throughout the eastern and southern states, to as far west as Arizona on the southern and Minnesota on the northern edges of its range. Within this range it is extirpated in both New Hampshire and West Virginia; Michigan populations are considered to be introduced rather than native.

Best Places to See

  • Sterling Forest (Orange County)

Identification Comments

General Description

Rattlebox is an annual, herbaceous, leguminous weed. It has an erect, hairy stem 10 to 40cm tall, with conspicuous stipules persisting along the upper stem. The leaves are alternate, sessile, pubescent, and lanceolate to linear, and 3 to 8 cm long. The flowers have a hairy, pale green calyx enclosing a pale yellow, two-lipped corolla. The distinctive fruits are very inflated, pendant legumes.

Best Life Stage for Proper Identification

This species is best identified when in fruit.

Similar Species

This is the only Crotalaria species native to New York (the introduced Crotalaria rotundifolia has been collected only from Orange County, and has spreading stems and reduced stipules). The fruits are an easy way to identify this plant, since their inflated structure is unique and should should not be confused with other species.

Best Time to See

Rattlebox flowers from July through September, and the fruits persist through November.

  • Vegetative
  • Flowering
  • Fruiting

The time of year you would expect to find Rattlebox vegetative, flowering, and fruiting in New York.

Rattlebox Images

Taxonomy

Rattlebox
Crotalaria sagittalis L.

  • Kingdom Plantae
    • Phylum Anthophyta
      • Class Dicotyledoneae (Dicots)
        • Order Fabales
          • Family Fabaceae (Pea Family)

Additional Resources

References

Clemants, Steven and Carol Gracie. 2006. Wildflowers in the Field and Forest. A Field Guide to the Northeastern United States. Oxford University Press, New York, NY. 445 pp.

Fernald, M.L. 1950. Gray's manual of botany. 8th edition. D. Van Nostrand, New York. 1632 pp.

Gleason, Henry A. and A. Cronquist. 1991. Manual of Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York. 910 pp.

Holmgren, Noel. 1998. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. The New York Botanical Garden, Bronx, New York.

New York Natural Heritage Program. 2010. Biotics database. New York Natural Heritage Program. New York State Department of Environmental Conservation. Albany, NY.

New York Natural Heritage Program. 2019. New York Natural Heritage Program Databases. Albany, NY.

Newcomb, Lawrence. 1977. Newcomb's Wildflower Guide: An Ingenious New Key System for Quick, Positive Field Identification of the Wildflowers, Flowering Shrubs, and Vines of Northeastern and North-Central North America. Little, Brown and Company. Boston.

Reschke, Carol. 1990. Ecological communities of New York State. New York Natural Heritage Program, New York State Department of Environmental Conservation. Latham, NY. 96 pp. plus xi.

Rhoads, Ann F. and Timothy A. Block. 2000. The Plants of Pennsylvania, an Illustrated Manual. University of Pennsylvania Press, Philadelphia, PA.

Weldy, T. and D. Werier. 2010. New York flora atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research http://www.fccdr.usf.edu/. University of South Florida http://www.usf.edu/]. New York Flora Association http://www.nyflora.org/, Albany, New York

Weldy, Troy W. and David Werier. 2005. New York Flora Atlas. [S.M. Landry, K.N. Campbell, and L.D. Mabe (original application development), Florida Center for Community Design and Research. University of South Florida]. New York Flora Association, Albany, NY. Available on the web at (http://atlas.nyflora.org/).

Links

About This Guide

Information for this guide was last updated on: January 18, 2008

Please cite this page as:
New York Natural Heritage Program. 2019. Online Conservation Guide for Crotalaria sagittalis. Available from: https://guides.nynhp.org/rattlebox/. Accessed January 17, 2019.

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