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Common beans originated in Latin America where its wild progenitor (P. vulgaris var. mexicanus and var. aborigenous) has a wide distribution ranging from northern Mexico to northwestern Argentina (Gepts 2001; Grigolo and Fioreze 2018; Centeno‐González et al. 2021). Secondary centers of diversification are East Africa and Europe, since the Phaseolus beans were introduced by Spaniards and Portuguese in the sixteenth and seventeenth centuries (Westphal 1974; Asfaw et al. 2009; Angioi et al. 2010).

It is important to note the diversity of trade routes that contributed to the dissemination of common beans throughout the world (Figure 3.1). Southwestern Native Americans moved many small white and black beans as well as mottled pinto types north from Mexican origins (Schumacher and Boland 2017). Native Americans maintained active trading of beans throughout North America and taught early seventeenth‐century European immigrants how to grow and prepare beans. The active sixteenth‐ and seventeenth‐century Spanish and Portuguese commerce (i.e., precious metals and the slave trade) moved large‐seeded beans from South America to Africa and Europe. Many of the beans currently grown in Africa have direct linkage to South American origins. European immigration and trade to North America resulted in introduction of these South American large‐seeded bean types (e.g., kidney and cannellini) (Kaplan 1965; Anon. 2020).

Fig. 3.1. Dry beans dispersal and trade routes.

Source: Adapted from Schuchert (2020) and Kelly (2020).

Peas, lentils, fava, and garbanzo beans originated within the Middle East and western regions of Asia. They have been a substantial part of the diet in these regions for millennia (Ladizinsky 1979; Tanno and Willcox 2006; Singh 2017). These bean types were traded along both the Eastern and Western trade routes resulting in general distribution throughout all of Europe and subsequently introduced to North America. Mung beans are commonly recognized to have originated from the Indian subcontinent of Asia (Prasad et al. 2016). These beans received broad‐based usage throughout South East Asian regions. Further, a diverse class of cowpeas (i.e., vigna, termed gram) were similarly domesticated in India and subsequently fully adopted within Africa.

Common beans are distinctive among a diverse and broad class of legumes. Carolus Linnaeus (1707–1778), the recognized authority in establishing modern taxonomy, observed these plants and designated them as Phaseolus vulgaris L. in his classic descriptive binomial genus and species taxonomy (the letter “L.” indicates the designation was original to Linnaeus). Figure 3.2 shows most common beans and pulses in the Fabaceae family.

Botanically, legumes are dicotyledonous seeds of plants belonging to the family Fabaceae (formerly identified as Leguminosae), which is one of the three largest families of flowering plants (Jin et al. 2019). These annual plants possess herbaceous stems with tri‐foliate leaves. The flowers are flat (butterfly or keel‐shaped) and develop seeds of various sizes, shapes, and colors, which are produced in a single cavity pod. All members of the Fabaceae have the characteristic of bearing pods, but the plants vary in size from the tiny wild vetches of the temperate zones to large tropical trees. The family is divided into three sub‐families with about two‐thirds of the total species in the sub‐family Papilionoideae, tribe Phaseoleae, subtribe Phaseolinae (Gepts 2001). This more recent nomenclature was prepared to provide names that are more representative of the dry beans within the family.

Fig. 3.2. Selected dry beans and pulses in Fabaceae family.

A comprehensive classification of Phaseolus has been prepared in a definitive monograph (Freytag and Debouck 2002). The genus Phaseolus also contains five domesticated species: in decreasing order of importance, common bean (Phaseolus vulgaris L.), lima bean (P. lunatus L.), runner bean (P. coccineus L.), tepary bean (P. acutifolius A. Gray), and year bean (P. polyanthus Greenman). Each has distinct adaptations and reproductive systems: mesic and temperate, predominantly self‐pollinated; warm and humid, predominantly self‐pollinated; hot and dry, cleistogamous; cool and humid, outcrossing; and cool and humid, outcrossing, respectively (Gepts 2001).

Food legumes traditionally refer to those species that are consumed directly in the human diet as mature dry seeds but occasionally as immature green seeds or as green pods with the immature seeds enclosed. They do not include species that provide leaf or stem tissues that are used as cooked or uncooked greens, and they also exclude oil‐bearing legumes [(e.g., soybeans (Glycine max (L.) Merr.)] and those used for forage and pasture [e.g., alfalfa (Medicago sativa L.), clover (different species belonging to the genus Trifolium L.), etc.] (Calles, 2016). An alternative term for the edible seeds of leguminous plants is “pulse,” from the Latin puls, meaning pottage.

The descriptive terminology “peas and beans” is frequently used interchangeably; most round‐seeded types with trailing or vining growth habits and many small leaflets are classed as peas. Examples of these include field peas, cannery peas, garden peas (all various forms of Pisum sativum L.), chickpeas (Cicer arietinum L.), and lentils (Lens culinaris M.). In contrast, beans are most commonly slightly flat‐seeded, with herbaceous stems bearing relatively large, well‐defined trifoliate leaves and growth habits varying from distinctly bushy to trailing and twining (Hardenburg 1927).

Although members of the family Graminae, comprising grasses and cereal grains [e.g., wheat (Triticum aestivum L.), maize, rice (Oryza sativa L.)], are the most extensively used plant foods and contribute the greatest levels of food energy globally, food legumes, or pulse crops, provide the greatest level of protein. The latter are particularly important in plant‐based diets to complement amino acids and enhance protein quality. It is noteworthy that soybeans are the legumes with greatest overall economic value in the world.

Legumes have a very well‐defined botanical classification of specific traits; however, the term legume appears to have a broad connotation when used in commercial trade or by consumers (Azani et al. 2017). Thus, the terminology used for describing leguminous plant products is rather complex and ambiguous. Key elements associated with dry bean and legume terminology are presented in Box 3.1. This outlined discussion is provided to assist the reader with an understanding of the broad nuances commonly associated with legume terminology.