Question: What is is a genus of plants in the pea family, Fabaceae, Tansy or Amorpha ?
Context: Clover or trefoil are common names for plants of the genus Trifolium (Latin, "tres" "three" + "folium" "leaf"), consisting of about 300 species of plants in the leguminous pea family Fabaceae.  The genus has a cosmopolitan distribution; the highest diversity is found in the temperate Northern Hemisphere, but many species also occur in South America and Africa, including at high altitudes on mountains in the tropics.  They are small annual, biennial, or short-lived perennial herbaceous plants.  Clover can be evergreen.  The leaves are trifoliate (rarely quatrefoiled (Four-leaf clover), cinquefoil, or septfoil), with stipules adnate to the leaf-stalk, and heads or dense spikes of small red, purple, white, or yellow flowers; the small, few-seeded pods are enclosed in the calyx.  Other closely related genera often called clovers include "Melilotus" (sweet clover) and "Medicago" (alfalfa or Calvary clover). Lathyrus latifolius, the perennial peavine, perennial pea, broad-leaved everlasting-pea, or just everlasting pea, is a robust, sprawling perennial in the Pea Family Fabaceae.  It is native to Europe but is present on other continents, such as North America and Australia, Amorpha Canescens (Amorpha brachycarpa, Leadplant, Leadplant amorpha, Downy indigo bush, Prairie shoestring, Buffalo bellows) is a 30 – tall perennial semi-shrub in the Pea family (Fabaceae) that is native to North America.  It has very small purple flowers with yellow stamens which are grouped in racemes.  Depending on location, the flowers bloom from late June through mid-September.  The compound leaves of this plant appear leaden (the reason for the common name "leadplant") due to their dense hairiness.  The roots can grow up to 5 m deep and can spread up to 1 m radially.  This plant can be found growing in well drained soils of prairies, bluffs, and open woodlands. Chamaecrista is a genus of flowering plants in the pea family, Fabaceae, subfamily Caesalpinioideae.  Members of the genus are commonly known as sensitive pea.  Several species are capable of rapid plant movement.  Unlike the related genera "Cassia" and "Senna", members of "Chamaecrista" form root nodules. Amorpha nana (dwarf indigo, dwarf indigobush, dwarf false indigo, fragrant indigo-bush, fragrant false indigo, dwarf wild indigo) is a 1-3 feet (30-90cm) tall perennial shrub in the Pea family (Fabaceae) which is native to North America.  It has vibrant green pinnate leaves and clusters of purple flowers.  The fruits are small pods.  Dwarf false indigo grows in dry prairies and rocky hillsides.  Amorpha nana likes rocky and sandy soil. Tansy ("Tanacetum vulgare") is a perennial, herbaceous flowering plant of the aster family, native to temperate Europe and Asia.  It has been introduced to other parts of the world including North America, and in some areas has become invasive.  It is also known as common tansy, bitter buttons, cow bitter, or golden buttons. Dermatophyllum is a genus of three or four species of shrubs and small trees in the subfamily Faboideae of the pea family, Fabaceae.  The genus is native to southwestern North America from western Texas to New Mexico and Arizona in the United States, and south through Chihuahua, Coahuila and Nuevo León in northern Mexico.  Members of the genus are commonly known as mescalbean, mescal bean or frijolito.  One of the common names of "Dermatophyllum secundiflorum" is Texas mountain laurel, although the name mountain laurel also refers to the very dissimilar and unrelated genus "Kalmia" (family Ericaceae) and the name laurel refers generally to plants in the unrelated order Laurales. 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. Ulex (commonly known as gorse, furze or whin) is a genus of flowering plants in the family Fabaceae.  The genus comprises about 20 species of thorny evergreen shrubs in the subfamily Faboideae of the pea family Fabaceae.  The species are native to parts of western Europe and northwest Africa, with the majority of species in Iberia. Sesbania is a genus of flowering plants in the pea family, Fabaceae, and the only genus found in tribe Sesbanieae.  Riverhemp is a common name for plants in this genus.  Notable species include the rattlebox ("Sesbania punicea"), spiny sesbania ("Sesbania bispinosa"), and "Sesbania sesban", which is used in cooking.  Plants of this genus, some of which are aquatic, can be used in alley cropping to increase the soil's nitrogen content.  The species of rhizobia responsible for nitrogen fixation in "Sesbania rostrata" is "Azorhizobium caulinodans".
Answer: Amorpha