Pea

The pea is a flowering plant grown as a pulse or animal feed, though the name usually refers to its seed or sometimes the pod. People eat peas as a vegetable. Some sources now classify it as *Lathyrus oleraceus*, but whether this change is needed or justified remains debated.

Each pod holds several seeds, or peas, which have either green or yellow cotyledons when mature. Botanically, pea pods are fruits because they contain seeds and develop from the flower’s ovary. Peas are annual plants with a one-year life cycle. They are a cool-season crop planted from winter to early summer, depending on the region. An average pea weighs between 100 and 360 milligrams. Immature peas—and in snow peas and snap peas, the tender pod as well—are eaten fresh, frozen, or canned as a vegetable. Varieties called field peas are grown to produce dry peas, such as split peas, from mature pods. These were the basis for pease porridge and pea soup, staples of medieval cuisine; in Europe, eating fresh, immature green peas was an innovation of early modern cooking.

The pea is most often green, occasionally golden yellow, or rarely purple, with pods about 4 to 10 centimeters long. Seeds are planted once soil reaches 10 °C, and plants grow best at 13 to 18 °C. They do not thrive in summer heat of warmer temperate or lowland tropical areas but grow well in cooler, high-elevation tropical regions. Many cultivars mature about 60 days after planting. Peas have both low-growing and vining cultivars. Vining types grow thin tendrils from leaves that coil around supports, climbing 1 to 2 meters high. A traditional support method uses pruned branches thrust upright into the soil, called pea sticks or pea brush. Metal fences, twine, or netting on a frame also work. In dense plantings, peas support each other. Pea plants can self-pollinate.

The pea genome has seven chromosomes—five acrocentric and two submetacentric. Its large genome size of 4.45 Gb made sequencing difficult compared to other legumes. The International Pea Genome Sequencing Consortium formed to create the first reference genome, and a draft assembly was announced in September 2019. It covers 88% of the genome (3.92 Gb) and predicted 44,791 gene-coding sequences. The assembly used the inbred French cultivar “Caméor.” A pea pangenome was published in 2022.

Carl Linnaeus gave the species the scientific name *Pisum sativum* in 1753, meaning cultivated pea. Some sources now treat it as *Lathyrus oleraceus*, though the need and justification for this change is disputed.

The word “pea” comes from the Latin *pisum*, which is a Latinization of the Greek *πíσον* (pison), a neuter variant of *πíσος* (pisos) for pea. It entered English as the noun *pease* (plural *peasen*), as in pease pudding. By analogy with other plurals ending in -s, speakers began treating *pease* as a plural and formed the singular by dropping the -s, giving “pea.” This is called back-formation.

There are many garden pea cultivars. Common ones include Alaska (55 days, smooth seeded), Tom Thumb (55 days, extra dwarf), Thomas Laxton (60–65 days), Mr. Big (60 days), Little Marvel (63 days), Early Perfection (65 days), Kelvedon Wonder (65 days), Sabre (65 days, powdery mildew resistant), Homesteader (67 days), Miragreen (68 days, tall climber), Serge (68 days, powdery mildew resistant, afila), Wando (68 days), Green Arrow (70 days), Recruit (70 days, powdery mildew resistant, afila), and Tall Telephone (75 days, tall climber). Dwarf varieties grow about 1 meter tall; extra dwarf types reach about 25 cm; tall varieties grow to about 2 meters with support.

Some peas lack the tough membrane inside the pod wall, giving tender edible pods. Snow peas have flat pods with thin walls, eaten very young. Snap peas (sugar snap peas) have rounded pods with thick walls, eaten before maturity. The term “sugar pea” can include both types or be synonymous with either. In British English, “mangetout” usually refers to snow peas but may also mean snap peas in other contexts.