spinach, annual plant (Spinacia oleracea) of the family Chenopodiaceae (goosefoot family), probably of Persian origin and known to have been introduced into Europe in the 15th cent. It is valued as a vegetable for the high vitamin and iron content of its leaves, and numerous varieties of the species are cultivated. New Zealand spinach belongs to the family Aizoaceae. Both families to which spinach plants belong are classified in the division Magnoliophyta, class Magnoliopsida, order Caryophyllales.

New Zealand spinach, succulent annual (Tetragonia expansa) of Australia, New Zealand, Japan, and S South America, grown for the edible leaves. The plant grows prostrate, often spreading to cover several feet. It is cooked like spinach. It is in the same family as the ice plant. New Zealand spinach is classified in the division Magnoliophyta, class Magnoliopsida, order Caryophyllales, family Aizoaceae.

Hardy, leafy annual (Spinacia oleracea) of the goosefoot family (Chenopodiaceae), used as a vegetable. The edible leaves, somewhat triangular and either flat or puckered, are arranged in a rosette, from which a seedstalk emerges. Spinach requires cool weather and deep, rich, well-limed soil to give quick growth and maximum leaf area; sowing seed every two weeks from early spring to late summer provides a steady supply. A nutritious vegetable, spinach is rich in iron and vitamins A and C.

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