Chamaecrista is a genus of approximately 367 species of flowering plants in the legume family Fabaceae (subfamily Caesalpinioideae), order Fabales. The genus was described by Moench in 1794 and is closely related to the genera Cassia and Senna, from which it is distinguished by its ability to form nitrogen-fixing root nodules — a trait unusual within the subfamily Caesalpinioideae.
Members of the genus are commonly known as sensitive peas, a name reflecting the capacity of several species for rapid, nyctinastic or touch-induced leaf movement. The leaves are typically pinnately compound, and the flowers are generally yellow with five petals in a nearly actinomorphic arrangement, followed by flat legume pods characteristic of the family.
Chamaecrista has a wide pantropical and warm-temperate distribution spanning the Americas (from Minnesota south to northern Argentina), sub-Saharan Africa, the Arabian Peninsula, Iran, the Indian Subcontinent, Indochina, China, Korea, Japan, Malesia, New Guinea, and Australia. The genus reaches its greatest diversity in South America and Africa.
Distribution
Chamaecrista has a wide pantropical and warm-temperate distribution encompassing the Americas from Minnesota to northern Argentina, sub-Saharan Africa, the Arabian Peninsula and Iran, the Indian Subcontinent, Indochina, China, Korea, Japan, Malesia, New Guinea, and Australia. The greatest species diversity occurs in South America and Africa.
Taxonomy Notes
Chamaecrista was described by Moench in Methodus (1794) and belongs to the family Fabaceae, subfamily Caesalpinioideae, order Fabales. It is distinguished from the closely related genera Cassia and Senna by its capacity to form root nodules, making it exceptional among caesalpinioid legumes. The GBIF backbone recognizes the authorship Chamaecrista Moench.
Ecology
Several species of Chamaecrista are capable of rapid plant movement in response to touch or changes in light. Unlike most members of subfamily Caesalpinioideae, Chamaecrista species form nitrogen-fixing root nodules, playing a role in soil nutrient cycling in the tropical and subtropical habitats they occupy.
