Edible Plants Table A comparison between common and edible Species in higher taxonomic groups (figures represent percentages of their respective totals) Taxonomic group Common species (n ¼ 270,000) Edible species (n ¼ 1790) Pterydophyta Gymnospermae Dicotiledoneae Monocotiledoneae 3.9 0.3 69.9 25.9 1.9 1.0 75.5 21.6 predictable that the most numerous families of plants would contain a higher number of edible species (Table 3) This relation seems to be valid since many of the most prolific families are also among the most productive in edible plants This is the case with the Compositae (Asteraceae), Leguminosae (Fabaceae), Gramineae (Poaceae), Euphorbiaceae, and Rubiaceae, which occupy the top positions in the ranking of both common species and edible species The most numerous of all plant families, the Orchidaceae, however, has few edibles Among the most suggestive cases is the number of genera in the Cactaceae family, which appears in the fourth place for edibles but is the 31st in the rank of common plants There is no clear relation among the ratios of number of species per genus that allows us to differentiate edible from common species Among families with the lowest ratios are the Asclepiadaceae (8.0), Cruciferae (8.6), and Rutaceae (10.0) Families that are richer in species per genus are the Begoniaceae (255.0), Aizoaceae (208.3), and Eriocaulaceae (92.3), yet they show no evidence of having experienced a process of selection, that is, of proclivity or rejection by humans, that would have led them to speciate toward palatability or distastefulness Of the 389 more frequently cultivated species considered by Nicholson et al (1969), the ranking goes as follows: Rosaceae (13.3% of total species), Leguminosae (8.5%), Gramineae (6.4%), Compositae (5.9%), Umbelliferae (5.4%), and Cruciferae (5.1%) They are followed by Palmae, Cucurbitaceae, Rutaceae, Alliaceae, Chenopodiaceae, Dioscoreaceae, Annonaceae, Ericaceae, Grossulariaceae, and 66 less prolific families Kunkel (1984) states that the Rosaceae is the richest family among food plants The analysis of a sample of 6222 items from his list confirms this assessment Rosaceae appears at the top of the list, comprising 5.8% of the cases, insofar as Leguminosae are split into Fabaceae (fourth place), Mimosaceae (sixth place), and Caesalpinaceae (82nd place) On the contrary, if the latter three families are considered as a unit, the Leguminosae stand in first place, comprising 6.7% of the sample The rank of the first 30 families is shown in Table Table 129 A ranking of the abundance of genera per plant family Common species Edible species Compositae (Asteraceae) Orchidaceae Leguminosae (Fabaceae, Mimosaceae) Gramineae (Poaceae, Bambusaceae) Rubiaceae Cruciferae (Brassicaceae) Umbelliferae (Apiaceae) Euphorbiaceae Liliaceae Asclepiadaceae Acanthaceae Labiatae (Lamiaceae) Palmae (Arecaceae) Scrophulariaceae Rutaceae Compositae Leguminosae Gramineae Cactaceae Umbelliferae Palmae Rubiaceae Labiatae Euphorbiaceae Cruciferae Rosaceae Myrtaceae Araceae Apocynaceae Moraceae Table A ranking of the abundance of edible species in the 30 most prolific familiesa 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Rosaceae Compositae (Asteraceae) Dioscoreaceae Fabaceae Liliaceae Mimosaceae Moraceae Ebenaceae Rubiaceae Myrtaceae Solanaceae Cactaceae Gramineae (Poaceae) Fagaceae Euphorbiaceae Cruciferae (Brassicaceae) Polygonaceae Palmae (Arecaceae) Ericaceae Rutaceae Umbelliferae (Apiaceae) Sapotaceae Guttiferae (Clusiaceae) Asclepiadaceae Caesalpiniaceae Annonaceae Zingiberaceae Vitaceae Araceae Cucurbitaceae a Edible Parts The richest family of common edible and nonedible species, the Orchidaceae, appears in 45th place Some plant genera are extremely abundant in edible species and may show particular tendencies toward a given kind of food (Table 5) For example, all of the 205 species of Rubus appearing in Kunkel’s list provide edible fruits Among them, there are three species whose leaves are also used as tea Similarly, the 80 or more species of Prunus provide edible fruits, as also occurs with Rosa spp and Ribes spp The majority of Piper species are used as black or white pepper or as a spice for curries Rumex provides 44 species with leaves used as vegetables and three species with edible roots Of the 100 edible species of Solanum, 59 are used only for their fruits, 20 species only for their tubers, 14 for both fruits and leaves, six species only for their leaves, and a single species exclusively for its seeds