Background

Numerous scientific researches conducted in the last few years have revealed that a diet rich in fibre, complex carbohydrates, vitamins and mineral salts, is the diet considered most ideal in order to maintain good health and prevent various illnesses. Fruit and vegetables are the food that contains a large quantity of vitamins and it is mainly because of this that many researchers have focused their attention on the studies of nutritional plants.

Many species have already been examined concerning this aspect but there are nevertheless many more which merit examination. Ethnobotany is a preliminary method of research, suitable for gathering information on the nutritional use of plants. It has been proven, time and time again, that the 'quack' medical knowledge handed down by the common people constitutes sources of information useful for scientific research and that many plants utilised exclusively in popular tradition, when exposed under scientific examination, have been found to be useful for different sectors in the industry [1]. Therefore, science and tradition have a strong connection between them; science, in fact, has often traditional origins.

Considering the fact that ethnobotany mainly concentrates on the individuation of plants with an applicative purpose, the authors, that have shown an interest in the argument for a long time, have completed a research conducted on the plants used as food and/or for aromatic purposes in popular, Sicilian tradition and have referred to, in this contribution, the results obtained.

One of the main objectives of this research is to individuate, amongst the plants of the Sicilian flora, those more or less known for their nutritional use and to provide suggestions on how to embark upon researches in the medical-nutritional field. In fact, many nutritional plants are also utilised for medical purposes and are often advised as a remedy in order to stabilise alternative functions of the human organism or simply to purify or cure some trivial pathologies.

To consider food as medicine is part of a culture and a millennial human practice, in fact, ancient documents, testify the consummation of many plants in order to prevent numerous illnesses. In the Ebers papyrus (around 1550 B.C.) barley, figs, olives, garlic and onions were mentioned amongst the plants of therapeutic use and today, more advanced scientific research reveals that human health is directly connected to nutrition.

This research aims to verify to what extent can popular tradition consent to the validation of the uses suggested by common people and to revaluate the consumption of the local species of flora by suggesting their integration as medicinal food in alimentary diet.

Methods of study

The studies have been conducted in Sicily (Fig. 1), an island with a surface of 25,707 square km, situated in the middle of the Mediterranean sea and is divided from Italy (the country to which it belongs) by a narrow section of water (Messina strait). Due to its unique position, vast variety of mountains and substrates and its mild climate, the island is rich in species.

Figure 1
figure 1

Map of research area.

Full size image

According to Di Martino and Raimondo [2] its vascular flora consists of 2361 taxa. This number has grown because many more taxa have been added, today in fact almost 3000 taxa can be counted, including those in the surrounding islands [3]. Due to its richness in species, Sicily is considered as one of the territories with the higthest vegetal biodiversity in the whole of the Mediterranean area. As for food plants of traditional use which are the subject of this research, the information has been collected by working on researches carried out in the island's rural communities and in particularly in the provinces of Agrigento, Caltanissetta, Enna, Messina, Palermo, Ragusa, Siracusa, Trapani, and in the Eolic islands (Messina), Egadi Islands and Pantelleria (Trapani), Pelagie islands (Agrigento) and Ustica (Palermo) which, in the past, have contributed to a lot of useful information concerning other researches [4–18]. Nevertheless, where the popular flora of Catania is concerned, the authors have referred exclusively to bibliographical researches instead [19–23]. This study has been carried out in two stages: during the first stage the cooperation of the local people, above all shepherds, farmers and old housewives has been indispensable and has provided valuable information about the plants of popular use, such as the vernacular name, parts used, period of collection and the receipts used in order to prepare traditional dishes; furthermore they also contributed in the collection of the plants. The second stage has been carried out in the Department of Botanical Sciences of the University of Palermo, where the collected species have been dehydrated and taxonomically determined using the analytical keys. The obtained exiccata have been kept in the Ethnobotanical Herbarium in the same Department. The study has been completed through an accurate bibliographical research which has allowed comparing the information collected in Sicily with the one known from literature [24–61].

The data reported has been shortened and summarised and placed in a scheme (Additional file 1) in which for every species the scientific, names, family, Italian vernacular names, used parts, traditional receipts and also the food uses recorded outside Sicily with the corresponding bibliographical references have been provided. In the scheme the species marked with the symbol @ are quoted as edible in the database PFAF [24]. The nomenclature used is the same adopted by Pignatti in Flora d'Italia [60] apart from the following families Apiaceae, Asteraceae, Brassicaceae, Fabaceae, Lamiaceae and Smilacaceae for which the authors referred to Jude et al., 1999 [61].

Furthermore, in Additional file 2, the scientific names and the corresponding Sicilian vernacular names are reported and, in Table 1, some traditional Sicilian vernacular culinary terms have been cited in the Additional file 1.

Table 1 Explanations of the Sicilian vernacular culinary terms used in Additional file 1
Full size table

This work has been expanded with data taken from Battiato [62] concerning edible seaweeds of traditional use and data concerning edible mushrooms in Sicily taken from [63][64][65]: this data is reported in a table (Table 2).

Table 2 Review of the mushrooms traditionally gathered and consumed in Sicily
Full size table

Discussion and results

The study conducted has consented the gathering of information on traditional uses linked with collective past memories and to nutritional habits of the Sicilian past conducted always in such a way so that they could take advantage of the territory resources. Furthermore, this has proven that even nowadays, in the island, there are ingredients and preparation methods used that remind us of ancient civilizations which have taken turns in dominating the island in the past centuries imposing their own customs. Greeks, Romans, Arabs, Normans, Svevian, and Spanish left a deep trace in the island not only concerning monuments and cultural traditions but also concerning the use of plants. Centaurea calcitrapa L., for instance, has been appreciated since the time of the Greeks and Ceratonia siliqua L., already known by the Romans, as showed by traces of its fruits in the pantries of the houses in Ercolano and Pompei after the eruption of the Vesuvio, are still as much used today as in the past. The researches conducted both in the internal part of the rural communities in Sicily and the coastal ones, have permitted to show that it concerns plants that are seasonally consumed, simply boiled or cooked in a pan with oil, garlic and pepper, often by also adding other vegetables; in fact, the expressions "ervi maritate" and "misticanza" which are recurrent, indicate the mixture of more vegetables in the preparation of soups and of other traditional dishes.

The study shows that 74 species are eaten boiled which are namely: 26 Asteraceae, 12 Brassicaceae, 9 Liliaceae, 6 Fabaceae, 3 Chenopodiaceae, 2 Apiaceae, 2 Malvaceae, 2 Polygonaceae, 2 Urticaceae and only 1 species of Amaryllidaceae, Boraginaceae, Capparidaceae, Iridaceae, Juncaceae, Lamiaceae, Orchidaceae, Papaveraceae, Plantaginaceae and Solanaceae.

62 are eaten raw or in salads and seasoned with oil, lemon or vinegar. Among them the Asteraceae are once more the most numerous with 23 species, following the Rosaceae with 8 species and the Brassicaceae and the Apiaceae with 6 species each, the Moraceae and the Valerianaceae with 3, the Fabaceae with 2 and the Ericaceae, the Liliaceae, the Malvaceae, the Myrtaceae, the Oxalidaceae, the Palmae, the Portulacaceae, the Punicaceae, the Rubiaceae, the Scrophulariaceae and the Ulmaceae with only one species. 55 species are fried for preparing side-dishes, vegetarian stuffing balls and omelets among them 15 Asteraceae, 10 Brassicaceae, 8 Liliaceae, 5 Fabaceae, 3 Chenopodiaceae, e only 1 of Agavaceae, Amaranthaceae, Apiaceae, Boraginaceae, Cactaceae, Capparidaceae, Caprifoliaceae, Caryohyllaceae, Dioscoreaceae, Plantaginaceae, Ranunculaceae, Smilacaceae, Solanaceae and Valerianaceae.

2 Asteraceae and 2 Liliaceae and only 1 species of Orchidaceae and Oxalidaceae are eaten roasted and seasoned with oil and salt. They are altogether 6 species, while 13 are used to prepare stews and namely 4 Asteaceae and 4 Fabaceae, 3 Brassicaceae and only 1 of Lamiaceae and Liliaceae.

Among the "erbe maritate" and "misticanze ": 12 Asteraceae, 4 Brassicaceae, 2 Caryophyllaceae, 2 Chenopodiaceae, 2 Fabaceae, 2 Urticaceae and only 1 species of Apiaceae, Boraginaceae and Portulacaceae.

2 Apiaceae and 2 Capparidaceae and only 1 species of Brassicaceae, Liliaceae, Myrtaceae and Oleaceae are pickled or conserved in oil or vinegar. 4 Rosaceae, 3 Moraceae and 1 of Cactaceae, Ericaceae, Myrtaceae, and Rubiaceae are used to prepare jams, and preserves of fruits. 3 Lamiaceae, and only 1 species of Lauraceae, Rosaceae and Rubiaceae are used to prepare liquors.

The aromatic species are 37 and namely 13 Lamiaceae, 9 Liliaceae, 4 Apiaceae, 4 Asteraceae and only 1 species of Brassicaceae, Fabaceae, Lauraceae, Papaveraceae, Pinaceae, Polygonaceae e Rosaceae.

The fruits are eaten fresh, dried or in a jam. Among the wild species such as: Crataegus azalorus L., Cydonia oblonga L., Pyrus amigdaliformis Vill., Rosa canina L., Rubus ulmifolius Schott., Sorbus domestica L., Celtis australis L., Myrtus communis L., Sambucus nigra L. e Arbutus unedo L., it is preferable to eat only small quantities in order to prevent unpleasant health implications; the "pruna servaggi" (Prunus spinosa L.), were commonly eaten in the past.

The fruits of Morus alba L. and M. nigra L., Pistacia vera L., Prunus dulcis (Miller) D.A. Webb., Castanea sativa Miller, Corylus avellana L., Punica granatum L., and di Opuntia ficus-indica (L.) Miller, are used very often, as those are all plants which have been introduced to different cultures in antiquity.

This last species have adapted so well along the coasts of the island so as to become a typical specimen of the Sicilian flora and also one of the symbols of the island. Its fruits are often eaten; jams and typical sweets are prepared such as: mustard which in Castelbuono, a village in the Park of Madonie, is called "pizichintì". With the skins of the fruit and the cladodes "pale", fried with oil, side dishes or sweet omelets are prepared if sugar is added. Other fruits which are considered a specimen of the Sicilian flora, because they have also acclimatised very well in the island, are the citrus fruits, rutacee which have origins in eastern and central Asia. Those species have been introduced in Europe and widely cultivated, spreading in the Mediterrenean area, particularly in Sicily where they have nevertheless never shown the tendency to a spontaneous growth.

Citrus sinensis (L.) Osbek, (sweet orange),Citrus Limon (L.) Burm. f. (lemon) and Citrus deliciosa Ten. (Mandarin orange), which is not reported in the summarizing table, because only the species with a big variety of cultivars in the island are cultivated.

Concerning the mandarin orange, big merit goes to the Botanical Gardens of Palermo, where between 1810 and 1820 the first specimen of Citrus deliciosa Ten. was introduced and in less than 30 years time from its introduction in Sicilian cultivation, it became one of the species which most changed the agricultural landscape of the island, contributing in generating the famous "Conca d'oro" (big extension of citrus with golden-like coloured fruits). Among the plants of big interest in Sicily for the production of edul fruits, the Vitis vinifera L. occupies one of the first places. Cultivated since the antiquity, it spread sporadically in the island. The fruit is eaten both fresh (grapes) and dried (raisin). The lattest is used to prepare traditional sweets "buccellati", cookies, cakes or can be added to various condiments.

The varieties of cultivated vine are numerous and are generally placed into two categories: vine used for the production of wine or vine used as fruit. The ones used to produce wine are collected between September and October. Also the olive tree (Olea europaea L.) plays an important role in the local economy. From Olea europaea L. var. sylvestris Hoffmgg et Link (wild olive) which grows spontaneously in Sicily and along the coasts of the Mediterranean Sea, derive the numerous cultural varieties of domestic olive oil, widely cultivated because of its edible fruits and its production of oil.

The olives, conserved or eaten with bread have been a characteristic food for Sicilian farmers for many centuries as is also the oil produced from them. Both green and black olives are eaten; they are first marinated in water, which must be changed every day, until they lose their bitter taste. They are eaten seasoned with bay, oregano, rosemary, thyme; in "brine" and also mashed.

Food plants used for different culinary purposes

Boiled

Ammi majus L., Anthemis precox L., Apium nodiflorum L., Asparagus albus L., Asparagus officinalis L., Asphodeline lutea L., Asphodelus microcarpus Salmz. et Viv., Atractylis gummifera L., Barlia robertiana Loisel, Beta vulgaris L. subsp. vulgaris, Beta vulgaris L. subsp. maritima (L.) Arcang., Borago officinalis L., Brassica nigra (L.) Koch, Brassica rapa L. subsp.sylvestris (L.) Janchen,Brassica tournefortii Gouan, Bunias erucago L., Capparis spinosa L., Cardus argyroa Biv., Carlina sicula Ten., Centaurea calcitrapa L., Centaurea nicaeensis All., Centaurea solstitialis L. subsp. schouwii (DC.)Dostal, Chondrilla juncea L., Cichorium intybus L., Chenopodium album L. subsp.album, Chrysanthemum coronarium L., Cynara cardunculus L.subsp. cardunculus, Crepis bursifolia L., Crepis vesicaria L. subsp. vesicaria, Cydonia oblonga L., Cynara cardunculus L. subsp. cardunculus, Hedysarum coronarium L., Hermodactylis tuberosus (L.) Salish., Hirschfeldia incana (L.) Lagr. F., Hyoseris radiata L., Juncus acutus L., Lactuca viminea (L.) Presl., Lathyrus articulatus L., Lathyrus odoratus L., Lathyrus sylvestris L., Lavatera trimestris L., Leontodon tuberosus L., Leopoldia comosa (L.) Parl., Lupinus albus L., Lycium europaeum L., Malva sylvestris L., Moricandia arvensis (L.) DC.,Narcissus tazetta L.subsp. tazetta, Onopordum illyricum L., Papaver rhoeas L. subsp. rhoeas, Pisum sativum L. subsp. sativum, Plantago lagopus L., Raphanus raphanistrum L. subsp. raphanistrum, Raphanus raphanistrum L. subsp. landra (Moretti) Bonnier, Rapistrum rugosum (L.) All., Rumex crispus L., Rumex thyrsoides Desf., Ruscus aculeatus L., Ruscus hypoglossum L., Scolymus grandiflorus Desf., Scolymus hispanicus L., Sinapis alba L., Sisymbrium irio L., Sisymbrium officinale (L.) Scop., Smilax aspera L., Sonchus oleraceus L., Taraxacum officinale Weber, Teucrium fruticans L., Tolpis virgata (Desf.) Bertol., Tragopogon crocifolius L., Tragopogon porrifolius L., subsp.australis (Jordan) Br.-Bl.Urospermum picroides (L.) Schmitd, Urtica membranacea Poiret, Urtica urens L..

Raw in salads

Ammi majus L., Anthemis precox L., Apium graveolens L., Apium nodiflorum L., Arbutus unedo L., Carthamus lanatus L., Celtis australis L., Centranthus ruber L., Ceratonia siliqua L., Chamaerops humilis L., Chondrilla juncea L., Cichorium intybus L., Chrysanthemum coronarium L., Crataegus azarolus L., Crataegus monogyna Jacq. subsp. monogyna, Diplotaxis erucoides (L.)DC., Diplotaxis tenuifolia (L.)DC., Eryngium campestre L., Fedia cornucopiae (L.) Gaertner, Ficus carica L., Hyoseris radiata L., Hypochoeris cretensis (L.) Chaub.et Bory, Lactuca serriola L., Lactuca viminea (L.)Presl., Lathyrus articulatus L., Leopoldia comosa (L.)Parl., Malva nicaensis All., Mespilus germanica L., Morus alba L., Morus nigra L., Myrtus communis L., Nasturtium officinale R. Br., Notobasis syriaca (L.) Cass., Oxalis pes-caprae L., Picris echioides L. Roth., Portulaca oleracea L., Prunus spinosa L., Punica granatum L., Pyrus amygdaliformis Vill., Raphanus raphanistrum L., Raphanus raphanistrum L. subsp. raphanistrum, Reichardia picroides (L.) Roth, Ridolfia segetum Moris, Rosa canina L., Rubia peregrina L., Rubus ulmifolius Schott., Scolymus grandiflorus Desf., Scolymus hispanicus L., Scolymus maculates L., Silybum marianum L., Sisymbrium irio L., Smyrnium olusatrum L., Sonchus asper L., Sonchus asper (L.) Hill subsp. nymanii (Tineo et Guss.) Hegi, Sonchus oleraceus L., Sonchus tenerrimus L., Sorbus domestica L., Tragopogon crocifolius L., Tragopogon porrifolius L. subsp. australis (Jordan) Br.-Bl., Urospermum picroides (L.) Schimtd, Valerianella eriocarpa Desf., Veronica anagallis-aquatica L..

Fried, browned in oil, in meat and vegetables balls, in omelettes

Agave americana L., Allium ampeloprasum L., Amaranthuis retroflexus L., Asparagus acutifolius L., A.albus L., A. officinalis L., Asphodeline lutea L., Beta vulgaris L. subsp. maritima (L.) Arcang., Beta vulgaris L. subsp. vulgaris, Borago officinalis L., Brassica nigra (L.) Koch, Brassica rapa L. subsp. sylvestris (L.) Janchen, (L.) Janchen Capparis spinosa L., Carduncellus pinnatus (Desf.) DC., Cardus argyroa Biv., Cardus pycnocephalus L., Chenopodium album L., Chondrilla juncea L., Clematis vitalba L., Cynara cardunculus L.subsp. cardunculus, Diplotaxis erucoides (L.) DC., Erucastrum virgatum (Presl) Presl, Fedia cornucopieae (L.) Gaertner, Foeniculum vulgare Miller subsp.vulgare, Hedysarium coronarium L., Hirsfeldia incana Hyoserys radiate L., Hypochoeris laevigata L., H.radicata L., Lathyrus clymenum L., Lathyrus ochrus (L.) DC., Lathyrus odoratus L., Lathyrus sylvestris L., Leopoldia comosa (L.) Parl., Lycium europium L., Onopordum illyricum L., Opuntia ficus-indica (L.) Miller, Plantago serraria L., Raphanus raphanistrum L., R. raphanistrum L. subps. landra (Moretti) Bonnier, Rapistrum rugosusm (L.) All., Ruscus aculeatus L., Ruscus hypoglossum L., Sambucus nigra L., Scolymus grandiflorus Desf., Scolymus hyspanicus L., Silene vulgaris (Moench.) Garcke subsp. angustifolia (Miller) Hayek, Sylibum marianum L., Sinapis arvensis L., Smilax aspera L., Sisymbrium officinale (L.) Scop., Sonchus oleraceus L., Tamus communis L., Taraxacum offcinalis Weber. Urospermum dalechampii (L.) Schmitd.

Roasted

Allium ampeloprasum L., Barlia robertiana Loisel, Cynara cardunculus L. subsp. cardunculus, Hermodactylis tuberosus (L.) Salsh., Leopoldia comosa (L.) Parl., Oxalis pes-caprae L.

Stewed

Atractylis gummifera L., Calamintha nepeta (L.) Savi, Cynara cardunculus L. subsp. cardunculus, Hirschfeldia incana (L.) Lagr.F., Lathyrus clymenum L., Lathyrus ochrus (L.) DC., Lathyrus odoratus L., Pisum sativum L. subsp. sativum, Raphanus raphanistrum L., Raphanus raphanistrum L. subsp. landra (Moretti) Bonnier, Ruscus aculeatus L., Silybum marianum L., Tamus communis L..

Mixed soups

Bellis perennis L., Beta vulgaris L. subsp. maritima (L.) Arcang., Beta vulgaris L. subsp. vulgaris, Borago officinalis L., Brassica nigra (L.) Koch, Foeniculum vulgare Miller subsp. piperitum (Ucria) Coutinho, Hypochoeris levigata L., Hypochoeris radicata L., Hypochoeris radicata L. subsp. neapolitana (DC.) Guadagno, Lathyrus articulatus L., Lathyrus clymenum L., Portulaca oleracea L., Raphanus raphanistrum L., Reichardia picroides (L.) Roth., Silene vulgaris (Moench.) Garcke, Silene vulgaris (Moench.) Garckesubsp. angustifolia (Miller) Hayek, Sinapis arvensis L., Sisymbrium officinale (L.) Scop., Sonchus asper L., Sonchus asper (L.) Hill subsp. nymanii (Tineo et Guss.) Hegi, Sonchus oleraceus L., Sonchus tenerrimus L., Tragopogon crocifolius L., Urospermum dalechampii (L.) Schmitd., Urospermum picroides (L.) Schmitd., Urtica membranacea Poiert, Urtica urens L..

Preserved in olive oil, brine or others

Allium ampeloprasum L., Apium nodiflorum L., Arabis turrita L., Capparis ovata Desf., Capparis spinosa L., Myrtus communis L., Foeniculum vulgare Millersubsp. vulgare, Olea europea L.

Jam

Arbutus unedo L., Crataegus azalorus L., Crataegus monogyna Jacq., Cydonia oblonga L., Ficus carica L., Morus alba L., Morus nigra L., Myrtus communis L., Opuntia ficus-indica (L.) Miller, Rubia peregrina L., Rubus ulmifolius Schott.

Liqueurs

Laurus nobilis L., Menta spicata L., Menta suaveolens Ehrh., Rubia peregrina L., Rubus ulmifolius Schott, Teucrium scordium L..

Spices

Allium ampeloprasum L., Allium nigrum L., Allium roseum L., Allium sativum L., Allium triquetrum L., Allium schoenoprasum L., Apium graveolens L., Asparagus acutifolius L., Asphodeline lutea L., Brassica fruticolosa Cyr., Calamintha nepeta (L.) Savi, Ceratonia siliqua L., Crithmum maritimum L., Cydonia oblonga L., Foeniculum vulgare Miller subsp. piperitum (Ucria) Coutinho, Helicrysum italicum (Roth) Don , Laurus nobilis L., Leopoldia comosa (L.) Parl., Mentha acquatica L., Mentha pulegium L., Mentha spicata L., Mentha suaveolens Ehrh., Origanum heracleoticum L., Origanum majorana L., Papaver setigerum DC., Petroselinum sativum Hoffm., Phagnalon saxatile (L.), Cass., Phlomis fruticosa L., Pinus pinea L., Rosmarinus officinalis L., Rumex scutatus L., Salvia officinalis L., Salvia sclarea L., Tanacetum vulgare L., Taraxacum officinale Weber, Thymus capitatus (L.) Hoffmanns et Link, Thymus spinolosus Ten.

Analogies between food uses of plants in Sicily and in other regions

The study has allowed showing how many species of the Sicilian flora are eaten, not only in Italy but also in many countries of the Mediterranean and many analogies between the uses of those plants in our island and in other territories have been discovered. After a bibliographical comparison, it results that Apium graveolens L., for instance, is eaten in North Africa, Cyprus, Spain, Turkey and many Italian regions as a seasoning or as a freshly boiled, green vegetable. A similar use has been recorded for Apium nodiflorum L. used in Sicily, Tuscany, Basilicata, Latium, Spain, Crete and Tunisia.

Common and similar uses are those of Capparis spinosa L., some species of Asparagus L., Beta L., Brassica L., Sonchus L., Borago officinalis L., Olea europea L., Portulaca oleracea L., Punica granatum L. and Rosmarinus officinalis L..

An analogy has also been shown for some species whose use is exclusive in the rural communities of the island but which are also similarly used in other Mediterranean countries. For istance Barlia robertiana Loisel., is eaten in San Pietro di Caltagirone, in the Catania province and also in Bodrum, in Turkey; Cardus pycnocephalus L., in the Petralie, mountain communities, in the Madonie which is a province of Palermo and in Cyprus; the seeds of Lathyrus clymenum L., in Sambuca di Sicilia, in the Agrigent province and in Tunisia; the shoots of Narcissus tazetta L subsp.tazetta. in Calatafimi in the Trapani province and in Egypt; Plantago lagopus L. in the Messina province and also in Tunisia and Crete;Prasium majus L. in the Palermo and Trapani provinces as also in Tunisia. A certain analogy has been discovered also among the customs of some Albanian etnical groups who settled in the past in Italy and namely the Arbëreshë Albanian etnical group in Lucania or that of Piana degli Albanesi in Siciliy.Origanum heracleoticum L., Ruscus aculeatus L., Salvia officinalis L., Urospermum dalechampii (L.) Schmidt-B. are used in the same way by both gropus. Oxalis pes-caprae L., Punica granatum L., Allium triquetrum L., Ceratonia siliqua L., show similar uses in Contessa Entellina (Siciliy), where lives a Greek-Albanian community and in Cyprus.

Noticeable similarities in the vernacular names have also been discovered. For example the name of "sparaci" and "sparangh'i" are respectively used in both Sicily and Cyprus to indicate some species of Asparagus L.; also "vurrania" and "voragho" for Borago officinalis L.; "finocchiu" and "finokyo" for Foeniculum vulgare Miller subsp.vulgare; "lipini" and "loupinarya" for Lupinus albus L. [42]. In Tunisia [31, 40]Capparis spinosa Desf. is known like "kabbar" or "quibbar" and in Siciliy like "chiappara"; Cichorium inthybus L. like "chkonia" and "cicoria" in our island, Cynara cardunculus L. subsp cardunculus like "kardouni" and "carduni" in Sicily.

Medicinal-food plants

The recipe used has also facilitated the gathering relevant information to the medicinal properties of many edible plants. In popular tradition, food is often indicated as medicine and the use of one herb or another is suggested, according to the cases. In order to avoid excessive constipation, it is recommended to consume the leaves of the Beta vulgaris L. and Beta vulgaris L. subsp. maritima (L.) Arcang. "gira", of Borago officinalis L. "vurrania", the tender parts of Cichorium intybus L. "cicoria", which are also considered refreshing; in order to encourage diuresis and to purify the organism, Foeniculum vulgare Miller subsp. vulgare "finocchiu" leaves should be used.

Sometimes the same plant can have different effects. For example, the fruit of Opuntia ficus-indica (L.) Miller "ficurinnia" can cause constipation if consumed with the seeds, without the seeds it becomes a laxative instead.

They are 37 plants among which 12 Asteracae, 4 Lamiaceae, 3 Brassicaceae, 3 Apiaceae, 2 Liliaceae, 2 Chenopodiaceae, 2 Malvaceae, 2 Rosaceae and only 1 species of Boraginaceae, Cactaceae, Fabaceae, Lauraceae, Moraceae, Polygonaceae e Ulmaceae. They are: Asparagus acutifolius L., Asparagus albus L., Beta vulgaris L. subsp. vulgaris, Beta vulgaris L. subsp. maritime (L.) Arcang., Borago officinalis L., Brassica nigra (L.) Koch, Celtis australis L., Centaurea calcitrapa L., Centaurea nicaeensis All., Chondrilla juncea L., Cichorium intybus L., Crataegus monogyna Jacq., Crepis vesicaria L. subsp. vesicaria, Cynara cardunculus L. subsp. cardunculus, Diplotaxis erucoides (L.)DC., Eryngium campestre L., Ficus carica L., Foeniculum vulgare Millersubsp. vulgare,, Hedysarum coronarium L., Hyoseris radiata L., Laurus nobilis L., Lavatera trimestris L., Malva nicaensis All., Opuntia ficus indica (L.) Miller,Origanum heracleoticum L., Origanum majorana L., Origanum vulgare L., Raphanus raphanistrum L. subsp. landra (Moretti) Bonnier, Reichardia picroides(L.) Roth., Ridolfia segetum Moris, Rosmarinus officinalis L., Rumex crispus L., Scolymus hispanicus L., Sonchus oleraceus L.,, Sonchus tenerrimus L., Sorbus domestica L., Taraxacum officinale L..

Potentially toxic plants

Furthermore, during the course of the research, some interesting data on the potential toxicity of some plants has emerged. In fact, in the Sicilian popular tradition, as already mentioned in a previous contribution [1], the food plants are separated into two categories: refreshing and purifying "erve frische" or are endowed with stimulating and disturbing effects "erve caure". The immoderate use of the last category may have toxic effects; that is why Sisymbrium officinale and some species of Sinapis should be consumed moderately; others like Capparis ovata Desf. and C. spinosa L. must be "cured" ("curate") namely kept in water or boiled like Lupinus albus L. e Smilax aspera L.. Very dangerous are: Clematis vitalba L. and Tamus communis L., which can be only eaten after having been cooked, and Atractylis gummifera L., of which only the aerial part can be used.

Edible seaweeds of traditional use in Sicily

It is important to underline that in Sicily the seaweeds are rarely used as food; their use is not well known and often limited only to some parts of eastern Sicily. According to Battiato's contribution [62] some Rodophyceae are considered to be edible in the island, for instance Nemalion helminthioides (Velley) Batters, (Nemalionales) a weed known in Palermo with the name of "Turkish spaghetti" ("spaghetti turchi"); Hypnea musciformis (Wulfen) Lamouroux (Hypneaceae) eaten in south-east Sicily; Gigartina acicularis (Wulfen) Lamouroux (Gigartinaceae), used to prepare omelettes in the Catania province where it is called "mauru rizzu", "capidduzzu" ; Gigartina teedii (Roth) Lamouroux (Gigartinaceae), known as "mauru, curaddina"; Grateloupia proteus Kuetzing (Cryptonemalies), called "mauru 'mpiriali", mauru ciuffu longu", mauru ciuffu curtu" and also used to prepare omelettes in the Catania province.

Edible mushrooms of traditional use in Sicily

The results of the contributes [63–65] show that 78 mushrooms are eaten in different rural communities of Sicily. Quite commonly used are the Pleurotus eryngii (DC.: Fr.) Quélet var. ferulae Lanzi known like "funci di ferra" and Pleurotus eryngii (DC.: Fr.) Quélet var. eryngii, "funci di panicauru", called as such because it is referring to the Sicilian vernacular names of the two apiacee under which they grow. As Table 2 shows many other mushrooms are consumed raw or stewed in order to prepare delicious traditional dishes.

Conclusion

Thanks to this study, and as also shown by the sinoptyc scheme (Additional file 1), the edible plants of traditional use in Sicily are 188; to those we must add Olea europaea L. and some species of Citrus L. commonly cultivated.

Some species are often used in the whole of the Sicilian territory: Borago officinalis for instance is used everywhere in Sicily while some others have a limited use in some areas of the island. This is the case of Agave americana, used only in Piazza Armerina; Allium nigrum in the Agrigent province;Amaranthus retroflexus in the Ragusa province; Ammi majus and Anthemis praecox respectively in Butera (CL) and Licata (AG); Crithmum maritimum in the Egadi Islands (TP); Mentha pulegium in the Aeolic Islands (ME); Lathyrs sylvestris in Messina, Cynara cardunculus in Agrigento and, sporadically, in the provinces of Palermo, Catania and Messina.

Exclusively in Sicily, like food plants are used 30 taxa. Among them, as shown by Pignatti in Flora d'Italia [60]Allium nigrum L., Anthemis praecox L.,Arabis turrita L., Hedysarum coronarium L.,Lathyrus sylvestris L,Oryzopsis miliacea (L.) Ash. et Schweinf,Raphanus raphanistrum L. subsp. raphanistrum and Tolpis virgata (Desf.) Bertol. are diffused in the whole of the Sicilian and Italian territory;Hypochoeris levigata L. is common only in Sicily and in the Island of Marittimo (TP), quite rare indeed in South Italy where, apart from Sicily, Cardus agyroa Biv. are common,Centaurea nicaensis All., Diplotaxis crassifolia DC. Carlina sicula Ten. and Erucastrum virgatum (Presl) Presl are endemic, while Carduncellus pinnatus (Desf.) DC., Hermodactylis tuberosus (L.) Salish., Hypochoeris cretensis (L.) Chaub. et Bory, Hypochoeris radicata L. subsp. neapolitana (DC.)Guadagno, Lathyrus articulatus L., Notobasis syriaca (L.) Cass., Papaver setigerum DC., Phagnalon saxatile (L.) Cass., Plantago serraria L., Ridolfia segetum Moris, Ruscus hypoglossum L.,Ruscus hypophyllum L.,Teucrium fruticans L. and Teucrium scordium L. are rather rare.

The discovery of their uses up to now not well known, is a stimulation to deepen the study on the plants of the local flora. Some wild species which are part of the daily life of the island, whome use seems to be new in the literature, could became object of bromatological and fitochimical studies. Those studies could possibly put on evidence the presence of substances important under the nutritional aspect that would allow emphasising species still unknown under this aspect and revaluing the natural and the cultural legacy of the island. With this work the authors, not only wish to give some information to attempt interdisciplinary studies but also hope to contribute in recovering the ancient culinary traditions and saving a legacy rich in information and intended to be lost if not written down. Since nowadays is growing the interest towards everything wihich is "natural" and it counts also for the food, the dishes which in the past connoted poor people could became today very "fancy". The continous flourishing of agritourism which offers traditional dishes to the visitors mostly prepared with the so-called "spontaneous vegetables", helps in spreading the knowledge and allows to appreciate their wholesomeness.

Reassesing the plants of the spontaneous flora, thus retrieving old traditional receipts, can help in introducing cultivations which could benefit the local economy.