The pea plant (Pisum sativum) is a member of the the Legume family (Fabaceae), which also contains beans, peanuts and alfalfa. Peas have been consumed in the Mediterranean and Middle East for at least 6,000 years, first being cultivated in Turkey 3,000 years ago. These plants are loved by farmers and gardeners for their ability to add nitrogen to the soil, thus enriching it for other crops. Today there are several subspecies of peas, including garden peas, snow peas, snap peas and field peas.
Garden peas (Pisum sativum var. sativum), also known as English peas, are the most common kind of pea plant. Like all other peas, garden pea plants are twining vines 1 to 1.5 feet in length, covered with tiny tendrils. They bear bright green, elongated oval-shaped leaves and five-petaled, irregular pink or white flowers which give way long green pods containing edible seeds.
Garden pea pods appear swollen and rounded when ready to harvest. The outer pod is inedible and must be removed to collect the peas within. Garden peas tend to lose their sweet flavor as soon as they are picked, and must therefore be quickly eaten, preserved or frozen.
Much-loved garden pea cultivars include the long-vined 'Alderman', also known as 'Tall Telephone', the early-maturing 'Alaska', and the near-leafess 'Novella'.
Another popular subspecies of pea is the snow pea (Pisum sativum var. macrocarpon), also known as the Chinese pea or mangetout pea. A snow pea plant resembles a garden pea plant in every aspect besides its pod. Snow pea pods are large, flat and somewhat translucent. The peas which they contain are not round and succulent as garden peas are, but are rather inconspicuous. Snow pea pods are eaten whole, and may be steamed, stir-fried or enjoyed fresh. They are widely used in Asian cuisine. One popular snow pea variety is 'Mammoth Melting Sugar', which produces sweet, toothsome pods up to 4.5 inches in length (See Reference 2) .
In the 20th century, a new kind of pea, called the snap pea, was hybridized by crossing an rare type of pea that had tightly packed pods with thick walls with a regular snow pea. The result was a pea with a thick and crunchy, yet edible pod containing large, round, succulent peas. The first variety of snap pea, 'Sugar Snap', became an All American Selection in 1979. Snap peas can replace snow peas in traditional Asian recipes, or garden peas in any dish requiring them.
Field peas (Pisum sativum var. arvense) are not as tender and delicate as other types of peas. They are often dried to make make split pea soup, rather than being consumed fresh or lightly cooked. They also make a nutrient-rich livestock fodder. Farmers sometimes plant field peas between other crops, simply for the purpose of adding fresh nitrogen to the soil.