Crotalaria purshii

Crotalaria purshii
Photo by Gil Nelson
Scientific classification
Kingdom:	Plantae
Division:	Magnoliophyta - Flowering plants
Class:	Magnoliopsida – Dicotyledons
Order:	Fabales
Family:	Fabaceae ⁄ Leguminosae
Genus:	Crotalaria
Species:	C. purshii
Binomial name
Crotalaria purshii DC.
Natural range of Crotalaria purshii from USDA NRCS Plants Database.

Common name: Pursh's rattlebox

Taxonomic notes

Synonyms: Crotalaria purshii var. purshii; C. purshii var. bracteolifera Fernald

Description

The Crotalaria genus, in general, are annual or perennial herbs or shrubs. The leaves can be simple or palmately 3-7 foliolate where the stipules are either lacking or are varying from minute to large and conspicuous and the leaflets are estipellate. The flowers are papilionaceous and are usually in terminal racemes but can but solitary. The bracts are subtending the pedicels are small to foliaceous, caduceus to persistent; the bracts are paired, minute to large borne on the pedicel or on the base of the calyx. The calyx is campanulate. The petals are yellow or yellow with purple streaks, they're rarely purple or blue; standard usually exceeding the wing and keel petal. There are 10 stamens, they are monadelphous, filaments of two lengths, the longer with small, subglobose anthers and the shorter with larger, linear anthers. The legume is inflated, few-many seeded, globose to more typically oblong-cylindric, sessile or rarely stalked (Radford 1964).

Specifically, for Crotalaria purshii, the plant is a perennial herb, growing up to 2-5 dm tall. It is densely appressed pubescent. The leaves are simple, the median and upper leaves are mostly linear to lanceolate, growing 3-6 (8) cm long, and 4-10 mm wide, the lower leaves are oblong to spatulate, growing 2-3 cm long, and 6-15 mm wide. The stipules of the the median and upper leaves are inversely sagittate decurrent 1/2 the length of the internode or more. The peduncle grows to 3-12 cm long, and is 3-6 flowered. The calyx is closely subtended by 2 linear, appressed bractlets, growing 4-6 mm long. The petals are yellow in color, and are equal or longer than the calyx. The legume is glabrous, oblong-cylindric, growing 2.5-4 cm long, and ca. 1 cm in diameter (Radford 1964).

Ecology

It is a legume.

Habitat

It can live in temperatures ranging from 10 to 28 degrees Celsius with an average of 115 cm of rain annually. It appears in a range of light conditions, from semi-shade to full sun, and a variety of mostly sandy soil types, including drying loamy sand, moist sand, clayey soil, peat, and loose sand.

Specific habitat includes grassy pineland communities such as loblolly pine communities, pine-scrub oak-palmetto woodlands, coastal dunes, and hillside bogs. It also can be found in disturbed areas, including roadsides and clobbered flatwoods.

Associated species include Baptisia simplicifolia, Liatris, Vernonia, Pityopsis, Eupatorium mohrii, E. rotundifolium, Pinus palustris, Quercus marilandica, Andropogon, Panicum, Vaccinium, Aristida stricta, Sabal minor, Ilex glabra, and others.

Phenology

Crotalaria purshii was observed flowering in sandhill and flatwood forests.

Flowering has been observed in April through October, and fruiting has been observed in May through October (FSU Herbarium).

Seed dispersal

According to Kay Kirkman, a plant ecologist, this species disperses by explosion mechanisms or by ants.

Fire ecology

This species is fire tolerant and occurs in burned areas (FSU Herbarium).

Use by animals

It is consumed by bobwhite quail.

References and notes

Florida State University Robert K. Godfrey Herbarium database. URL: http://herbarium.bio.fsu.edu. Last accessed: June 2014. Collectors: Harry E. Ahles, Loran C. Anderson, Grafton Anding, Wilson Baker, M.L. Bomhard, R. S. Campbell, Andre F. Clewell, Richard R. Clinebell II, D. S. Correll, Delzie Demaree, Robert K. Godfrey, J. Haesloop, A. Johnson, Lisa Keppner, Ed Keppner, R. Komarek, R. Kral Paul C Lemon, M. Jenkins, Sidney McDaniel, Thomas E. Miller, John B. Nelson, R. A. Norris, C.K. Pearse, A. B. Pittman, H. R. Reed, Annie Schmidt, Kenneth Lee Tyson, and Jean Wooten. States and Counties: Alabama: Baldwin, Conecuh, Geneva, and Washington. Florida: Bay, Calhoun, Dixie, Duval, Franklin, Gadsden, Gulf, Lee, Leon, Liberty, Madison, Santa Rosa, Sarasota, Wakulla, Walton, and Washington. Georgia: Berrien, Coffee, Grady, Seminole, Thomas, and Tift. Louisiana: Washington. Mississippi: George, Jackson, and Pearl River. North Carolina: Sampson. South Carolina: Dorchester and Lee.

Radford, Albert E., Harry E. Ahles, and C. Ritchie Bell. Manual of the Vascular Flora of the Carolinas. 1964, 1968. The University of North Carolina Press. 584-5. Print.