Amorpha Explained

Amorpha is a genus of plants in the pea family, Fabaceae. All the species are native to North America, from southern Canada, most of the United States (US), and northern Mexico. They are commonly known as false indigo. The name Amorpha means "deformed" or "without form" in Greek and was given because flowers of this genus only have one petal, unlike the usual "pea-shaped" flowers of the Faboideae subfamily. Amorpha is missing the wing and keel petals.^[1]

The desert false indigo or indigo bush (Amorpha fruticosa), is a shrub that grows from 3 m to 5 m tall. The species is considered a rare species in the US state of West Virginia and in the Canadian provinces of Manitoba and Ontario, but is considered an invasive plant in some areas of the northeastern and northwestern United States and in southeastern Canada, beyond its native range, and has also been introduced into Europe.

The lead plant (Amorpha canescens), a bushy shrub, is an important North American prairie legume. Lead plant is often associated with little bluestem (Schizachyrium scoparium), a common prairie grass. Native Americans used the dried leaves of lead plant for pipe smoking and tea.

Amorpha species are used as food plants by the larvae of some Lepidoptera species including Schinia lucens, which feeds exclusively on the genus.

Amorphol, a rotenoid bioside, can be isolated from plants of the genus Amorpha.^[2]

Species

Amorpha comprises the following species:^{[3] [4] [5]}

• Amorpha apiculata Wiggins

• Amorpha californica Torr. & A. Gray—California false indigo, mock locust
  • var. californica Torr. & A. Gray
  • var. napensis Jeps.
• Amorpha canescens Pursh—leadplant
• Amorpha confusa (Wilbur) S.C.K. Straub, Sorrie & Weakley
• Amorpha crenulata Rydb.^[6] (endangered)

• Amorpha fruticosa L.—desert false indigo
• Amorpha georgiana Wilbur—Georgia false indigo
• Amorpha glabra Desf. ex Pers.—mountain false indigo

• Amorpha herbacea Walter—clusterspike false indigo
  • var. herbacea Walter
  • var. floridana (Rydb.) Wilbur

• Amorpha laevigata Nutt.—smooth false indigo

• Amorpha nana Nutt.—dwarf false indigo
• Amorpha nitens Boynton—shining false indigo

• Amorpha ouachitensis Wilbur—Ouachita false indigo

• Amorpha paniculata Torr. & A.Gray—panicled false indigo

• Amorpha roemeriana Scheele—Roemer's false indigo
• Amorpha schwerinii C.K. Schneid.—Schwerin's false indigo

Species names with uncertain taxonomic status

The status of the following species is unresolved:

• Amorpha arborea Schkuhr
• Amorpha californica Nutt.
• Amorpha coerulea Lodd.
• Amorpha colorata Raf.
• Amorpha crocea hort. ex Lavallée
• Amorpha dealbata hort. ex Lavallée
• Amorpha discolor Raf.
• Amorpha elata Hayne
• Amorpha elatior hort. ex Lavallée
• Amorpha flexuosa Raf.
• Amorpha gaertneri K.Koch
• Amorpha gardneri K.Koch
• Amorpha glauca Raf.
• Amorpha incana Engelm.
• Amorpha laevigata Nutt.
• Amorpha lewisii Lodd. ex Loudon
• Amorpha ludoviciana hort. ex Lavallée
• Amorpha ludwigii K.Koch
• Amorpha lutea Raf.
• Amorpha macrophyla Raf.
• Amorpha marginata hort. ex Lavallée
• Amorpha mimosifolia Voss
• Amorpha nana Nutt.
• Amorpha nonperforata Schkuhr
• Amorpha ornata Wender.
• Amorpha pedalis Blanco
• Amorpha perforata Schkuhr
• Amorpha rabiae Lex.
• Amorpha retusa Raf.
• Amorpha sensitiva Voss
• Amorpha tenesseensis Schult.
• Amorpha tomentosa Raf.
• Amorpha verrucosa Raf.

Hybrids

The following hybrid has been described:

• Amorpha × notha E.J.Palmer

Notes and References

1. Book: Gledhill D. . The Names of Plants . Cambridge University Press . 2008 . 978-0-521-86645-3 . 24 December 2008.
2. Kasymov AU, Kondratenko ES, Abubakirov NK . 1974 . Structure of amorphol—A rotenoid bioside from plants of the genus Amorpha . . 10 . 4 . 470–473 . 10.1007/BF00563810 .
3. Web site: ILDIS LegumeWeb entry for Amorpha . . International Legume Database & Information Service . Cardiff School of Computer Science & Informatics . 7 July 2014 .
4. Web site: GRIN species records of Amorpha . USDA . USDA . ARS . Agricultural Research Service . National Genetic Resources Program . Germplasm Resources Information Network—(GRIN) [Online Database] . National Germplasm Resources Laboratory, Beltsville, Maryland . 7 July 2014 . https://web.archive.org/web/20150924121952/http://www.ars-grin.gov/cgi-bin/npgs/html/splist.pl?541 . 2015-09-24 . dead .
5. Web site: The Plant List entry for Amorpha . 2013 . . . 7 July 2014 .
6. Some sources treat Amorpha crenulata as a synonym (variety) of Amorpha herbacea.