Cajanus scarabaeoides (L.) Thouars

Classification and Relatives

Cajanus scarabaeoides (L.) Thouars is a very close wild relative of Cajanus cajan, commonly known as pigeonpea. It is a dicot angiosperm belonging to the family Fabaceae.

Growth Cycle

This species can grow as either an annual or a perennial plant, which makes it a flexible crop for subsistence farmers.

Branch Characteristics

Its branches can be straight or winding, and reach up to 135 cm in length.

Leaves and Flowers

It has pinnate leaves, typically arranged in a trifoliate pattern, and produces yellow flowers marked with red veins.

Pod Dimensions

Its pods are oblong in shape, usually measuring 11–34 mm in length and 6–10 mm in width.

Pod Appearance and Seed Count

The seedpods are densely covered with a mix of short and long hairs, are typically dark purple, and hold between 1 and 7 seeds each.

Seed Characteristics

The seeds themselves range from 2.4–4 mm long, 1.8–3 mm wide, and 1–2 mm thick, and are either solid black or speckled.

Seed Yield Comparison

Compared to cultivated pigeonpea, Cajanus scarabaeoides has a higher percentage of seeds per pod: 74% versus 20%. It also produces more multiseed pods, with an average of 6.04 seeds per pod compared to 3.0 seeds in cultivated pigeonpea.

Native Range Overview

Cajanus scarabaeoides is the most widely distributed wild relative of Cajanus cajan, and is native to many countries across both temperate and tropical zones.

African Distribution

In Africa, it is native to Madagascar.

Temperate Asian Distribution

In temperate Asia, it is native to China, Japan and Taiwan.

Tropical Asian Distribution

In tropical Asia, it is native to Bangladesh, Bhutan, India, Nepal, Pakistan, Sri Lanka, Myanmar, Thailand, Vietnam, Indonesia, Malaysia, Papua New Guinea and the Philippines.

Oceanian Distribution

In Oceania, it is native to Australia and Fiji.

Distribution in China and Taiwan

Within Asia, it is the most commonly distributed wild species of the genus Cajanus, and grows abundantly in Taiwan and the Chinese provinces of Yunnan, Guizhou, Guangxi, Guangdong, Hainan and Fujian.

Local Names in China

This species has several local names in China: it is called “Man Cao Chong Duo” in Mandarin Chinese, “Shui Kom Ts’o” in the Guangdong dialect, and “Jia Yan Pi Guo” in the Yunnan dialect.

Livestock Use

In China, Cajanus scarabaeoides is sometimes used as fodder, and has been shown to be effective at reducing diarrhea in cattle.

Medicinal Uses

Additionally, its leaves are used in traditional medicine to improve indigestion and reduce excessive urine production.