Yellow Nutsedge (Cyperus esculentus)

Description

Cyperus esculentus (also called chufa sedge, nut grass, yellow nutsedge, tiger nut sedge, edible galingale or earth almond) is a crop of the sedge family widespread across much of the world. It is found in most of the Eastern Hemisphere, including Southern Europe, Africa and Madagascar, as well as the Middle East and the Indian subcontinent. Cyperus esculentus can be found wild, as a weed, or as a crop. Evidence exists for its cultivation in Egypt since the sixth millennium BC, and for several centuries in Southern Europe. In Spain, C. esculentus is cultivated for its edible tubers, called earth almonds or tiger nuts, for the preparation of horchata de chufa, a sweet, milk-like beverage. However, in most other countries, C. esculentus is considered a weed. Cyperus esculentus is an annual or perennial plant, growing to 90 cm (3.0 ft) tall, with solitary stems growing from a tuber. The plant is reproduced by seeds, creeping rhizomes, and tubers. Due to its clonal nature, C. esculentus can take advantage of soil disturbances caused by anthropogenic or natural forces. The stems are triangular in section and bear slender leaves 3–10 mm (1/8 to 1/2 inches) wide. The spikelets of the plant are distinctive, with a cluster of flat, oval seeds surrounded by four hanging, leaf-like bracts positioned 90 degrees from each other. They are 5 to 30 mm (about 3/8 to 1 1/8 inches) long and linear to narrowly elliptic with pointed tips and 8 to 35 florets. The color varies from straw-colored to gold-brown. They can produce up to 2420 seeds per plant. The plant foliage is very tough and fibrous and is often mistaken for a grass. The roots are an extensive and complex system of fine, fibrous roots and scaly rhizomes with small, hard, spherical tubers and basal bulbs attached. The tubers are 0.3 – 1.9 cm (1/8 to 3/4 inches) in diameter and the colors vary between yellow, brown, and black. One plant can produce several hundred to several thousand tubers during a single growing season. With cool temperatures, the foliage, roots, rhizomes, and basal bulbs die, but the tubers survive and resprout the following spring when soil temperatures remain above 6 °C (43 °F). They can resprout up to several years later. When the tubers germinate, many rhizomes are initiated and end in a basal bulb near the soil surface. These basal bulbs initiate the stems and leaves above ground, and fibrous roots underground. C. esculentus is wind pollinated and requires cross pollination as it is self–incompatible.