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Job's tears

life science Maturity 9-11 Next article →

Job's tears, scientifically known as Coix lacryma-jobi, is a tall, perennial grass. It belongs to the Poaceae family, which includes many common grasses. This plant is native to Southeast Asia, including countries like India, Myanmar, China, and Malaysia. It is a robust, branched plant that can reach heights between 1.20 meters and 1.80 meters.

Jobs tears
Jobs tears

Because it grows well in higher elevations, it often thrives where rice and corn cannot grow. This makes it a very important plant for specific environments.

The plant is monoecious, meaning it has both male and female flowers on the same plant. These flowers grow in clusters called inflorescences. The male parts project upward and feature yellow stamens. The female parts include one or two yarn-like stigmas. A unique feature of this species is the involucre. This is a hardened bract, or a specialized leaf-like structure, that covers the base of the flowers. In some varieties, these involucres become very hard, glossy, and shell-like. These shells protect the seeds and can look like white, pearly ovals.

There are several distinct varieties of Job's tears. The wild variety, Coix lacryma-jobi var. lacryma-jobi, produces these hard, bony involucres. These are often used for crafts. Another variety, Coix lacryma-jobi var. ma-yuen, is a cultivated cereal crop. It has a much softer shell and is used in traditional medicine across Asia. A third variety, Coix lacryma-jobi var. puellarum, is found from Assam to Yunnan. It is the smallest variety, with seeds measuring only 4mm in diameter. Finally, var. stenocarpa grows from the Eastern Himalayas to Indochina and has long, cylindrical involucres.

History shows that humans have used this plant for thousands of years. In north-central China, Neolithic pottery residue suggests Job's tears were used to brew beer around 3000 BC. Archaeological evidence in Japan, such as phytoliths from the Early Jōmon Period, dates the plant's presence there to around 4000 BC. In northeastern India, remains have been found dating to approximately 1000 BC. The name "Job's tears" was introduced to Europe by Arabic merchants during the Middle Ages. They named it after the biblical figure Job, associating the pearly seeds with his story. They used the seeds to create misbaha, which are prayer beads.

Culturally, the plant serves many purposes. In Japan, the seeds are sometimes called juzu-dama, and children have used them for necklaces. In Southeast Asia, various ethnic groups use the beads for clothing. The Akha people sew them onto headwear and jackets. The Karen people select oblong seeds specifically for their jackets. In Borneo, tribes like the Kelabit and Murut use the beads for ornamentation. In the Philippines, the Tboli people have used the seeds to make bead curtains or even woven baskets. This shows how a single plant can support both food and art.

In modern times, the plant is often sold in Asian supermarkets under the name "Chinese pearl barley." This is actually a mistake in labeling. Job's tears is not closely related to true barley, which belongs to a different genus. However, the name persists because the grains look similar. In China, large-scale cultivation occurs in provinces such as Fujian, Jiangsu, Hebei, and Liaoning. The plant has also naturalized in the southern United States and the New World tropics. This wide distribution shows how successful the species is in different climates.

Beyond its uses in food and crafts, there is interesting science behind its growth. The plant produces specific proteins called α-zein prolamins. Scientists have observed that these proteins have undergone rapid evolutionary divergence. This happened through copy-number changes in their genes. This biological complexity adds to the plant's unique identity. From ancient beer brewing to modern beadwork, Job's tears remains a versatile part of human history and biology.

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