Botanical Identification of Senna (Cassia senna)

To identify Senna (Cassia senna) accurately, examine its morphological characteristics, taxonomic classification, and diagnostic features.

Senna (Cassia senna) Monograph

Scientific Classification

Senna, or Cassia senna, belongs to the plant kingdom Plantae, division Magnoliophyta, class Fabales, order Fabales, family Fabaceae, genus Cassia, and species Cassia senna. This classification places it within the legume family, known for its nitrogen-fixing abilities and medicinal uses.

The following table shows the full taxonomy of this medicinal plant.

Botanical Nomenclature and Synonyms

Cassia senna is the scientific name for the plant commonly known as Senna. It was first described by the botanist Carl von Linné, hence the author citation is Linné. The plant has several synonyms, including Senna tora and Senna occidentalis, which reflect its historical classification. It is also known by various common names such as Indian Senna and Senna tree.

Morphological Characteristics

Senna, or Cassia senna, is an erect, herbaceous annual plant with a branched root system. It has smooth, slender stems that can grow up to 1.5 meters tall. Its bipinnately compound leaves are green with a slightly hairy underside. The plant produces racemose inflorescences with bright yellow flowers that have five petals. The fruit is a slender, twisted pod containing numerous flat, kidney-shaped seeds.

Diagnostic Identification Features

Senna (Cassia senna) can be distinguished by its bipinnately compound leaves with small, ovate leaflets, yellow flowers in terminal clusters, and cylindrical, yellow pods that split open to release seeds. It differs from similar species like Cassia tora by its smaller, more delicate leaves and distinct floral structure.

Natural Habitat and Geographic Distribution

Senna (Cassia senna) is native to tropical and subtropical regions of Africa, southern Asia, and the Middle East. It thrives in warm climates with ample sunlight and well-drained, sandy or loamy soils. It typically grows at altitudes between 0 and 1,500 meters.

Phenology and Growth Cycle

Senna (Cassia senna) typically blooms from late spring to early summer, producing bright yellow flowers. Seed formation occurs in late summer to early fall. For identification purposes, the plant is best harvested during the flowering stage to ensure accurate botanical recognition.

Phylogenetic Relationships

Senna is closely related to species within the genus Cassia, part of the legume family Fabaceae. It shares key family traits such as compound leaves and pod fruits. Its closest relatives include Cassia tora and Cassia alata, which also exhibit similar morphological and chemical characteristics.