Humans have gathered wild edible plants since ancient times, and the plants have become part of the human diet and traditional food systems [1]. Eating flowers is a legacy of the many cultures that have been using wild edible plants in their food traditions for centuries [2]. Many species of edible flowers were already used in ancient Greece and Rome, in medieval France, and Victorian England as relishes and flavor enhancers of many dishes ^[3][4][3,4]. Many ancient texts refer to edible flowers. For example, the Bible cites dandelions as one of the “bitter herbs” eaten as salads, while in the Song of Solomon saffron, the stamens of Crocus sativus, is mentioned [5]. In Italy, evidence on the use of flowers can be found in some refined preparations, such as, for example, vino violatum (violet wine) or rosatum (rose petal wine), safflower flower sauce, and marjoram flower meatballs, whose recipes are reported in Apicius De Re Coquinaria, a famous cookbook from imperial Rome (1st century AD) [6]. During the Middle Ages, the marigold flower was a common ingredient in salads, and its flowers appeared in numerous preparations. In fact, during the Renaissance (15th and 16th centuries) cooking with flowers and making candied fruits was a very common practice. In his Libro de arte Coquinaria, the cook Maestro Martino reported in his recipe book a “menestra de fior de sambuco” (elderflower soup), [7] while Bartolomeo Scappi presented the preparation for a rose water and a borage flower confetto [8]. From the Baroque period, researchwers can mention Gerolamo Mei, who reported numerous recipes based on flowers, including biscuits with Citrus aurantium flowers, violet syrups, and pink sugar, composed of violets, hyssop, and roses [9]. Flowers have traditionally been used in cooking in various cultures, not only for their aesthetic appearance but also for their specific taste and smell [10]. Edible flowers are traditionally consumed in salads or used to prepare cakes, fritters, drinks, teas, and liqueurs, served as aroma enhancers, or as a side dish. In many cultures, fresh flowers are eaten as snacks, especially by children, for the sweet taste due to the nectar. Nowadays, the interest in the use of edible flowers is increasing, especially among chefs, not only for their aesthetic properties but also because of their proven health benefits ^[11][12][11,12]. The search for new food products is also a pursuit of new colors, textures, and flavors that can be achieved with the use of edible flowers [13]. Moreover, consumers are increasingly choosing food products containing natural ingredients and edible flowers to bring interesting elements to culinary and dietary habits [14]. From this perspective, the interest in edible flowers is continuously increasing, and many researchers have focused their attention on the nutritional composition, including the acceptability, the antioxidant and antimicrobial activities, the effects on human health, and the safety issues [15]. However, because of the low availability (i.e., short blooming period and in limited places) and poor post-harvest life, edible flowers are commonly utilized by the local people during their respective flowering period only. The use of flowers as food cannot, however, be considered a new discovery, but a rediscovery of ancient ethnobotanical traditions [16]. The role of ethnobotanical research is, in fact, to avoid the loss of the traditional knowledge concerning plant lore, and in this context, the ethnobotany of food plants is a fairly well-developed research field in several European geographical areas and social communities ^{[17][18][19][20]}[17,18,19,20]. In this scenario, according to Pieroni et al. [21], focusing on the traditional uses of edible flowers can constitute an important tool for analyzing and preserving the traditional ecological knowledge (TEK) and cultural diversity in the Mediterranean basin.

The elderberry (Sambucus nigra L.) is the most cited species (20 papers, five countries); it is a deciduous shrub native to Europe, introduced into various parts of the world, including E. Asia, N. America, New Zealand, and the southern part of Australia ^[22][109]. By the action of birds, its seeds are rapidly spread, colonizing the forest edges, areas along the roads, rails, and fence lines. Elderberry shrubs bloom over the summer from June to August, depending on the climate. The white, scented flowers are grouped in large corymbs. The elderberry flowers (such as the related S. racemosa L.) are dipped into a light batter and then fried to make fritters or used in the preparation of pancakes and omelettes. The flowers are also used for the preparation of juice, jam, jellies, and beverages and as an aromatizer. The odor of elderflowers has been shown to be related to the occurrence of 59 compounds: cis-Rose oxide, nerol oxide, hotrienol, and nonanal contribute to the characteristic elderflower odor, whereas linalool, α-terpineol, 4-methyl-3-penten-2-one, and (Z)-β-ocimene contribute with floral notes ^[23][110]. The flower extract has a higher content of phenolic compounds, such as rutin, chlorogenic acid, and rosmarinic acid ^[24][111]. Although currently they are mainly used in the food industry as flavoring agents due to their phytochemical composition and related bioactivities, elderflowers or their extracts are becoming attractive for other uses, such as food supplements and nutraceutical ingredients, and as raw materials for the pharmaceutical industries. The beneficial health-promoting effects of elderflowers are well known, including effects against degenerative diseases (cardiovascular and inflammatory diseases), cancer, and diabetes, and also present antioxidant, anti-inflammatory, immune-stimulating, chemo-preventive, and atheroprotective effects ^[25][112]. S. nigra flowers are widely used also in the folk phytotherapy in Albania, Algeria, Italy, and Spain: the internal use is applied to the treatment of bronchial diseases, colds, and abdominal pains and as an anti-inflammatory, or they are used as antipyretics, diuretics, digestives, diaphoretics, anti-rheumatics, and galactagogues (e.g., ^{[26][27][28][29][30]}[113,114,115,116,117]). As a topical application, the flowers are used for the treatment of conjunctivitis, wounds, burns, and rheumatic pains (e.g., ^[31][32][33][32,118,119]). The elderberry flower infusion is also used as a skin toner and whitener ^[34][120].

The black locust or false acacia (Robinia pseudacacia L.) is a deciduous tree native to North America and naturalized elsewhere in temperate areas of Europe, Southern Africa, and Asia and is considered an invasive species in some areas. This species was probably introduced to Europe in 1601 ^[35][121]. In several European databases, it is classified as highly invasive and is now listed amongst the 40 most invasive woody angiosperms globally ^[36][122]. In the time of flowering (May and June), black locust flowers are one of the most important sources of honey production ^[37][123]. R. pseudacacia flowers (14 papers, five countries) are commonly used in the preparation of omelettes, fritters, syrup, and liqueur and are also eaten as snacks. The chemical composition shows 24.55% protein, 8.51% ash, 40.97% total sugar, and 160.44 mg of ascorbic acid on a dry matter basis, respectively. The free sugar is mainly composed of fructose, sucrose, and glucose ^[38][124]. Linalool, cis-β-ocimene, methyl anthranilate, phenyl ethyl alcohol, germacrene D, (E)-α-bergamotene, benzeneacetic acid methyl ester, (Z)-nerolidol, and indole are important contributors to the pleasant aroma of the flowers of R. pseudacacia ^[39][125]. The black locust flower polyphenolic extract contains a significant percentage of polyphenolic compounds and presents good antioxidant and antitumoral activity ^[40][126]. R. pseudacacia flowers are used in Italy as an infusion for the treatment of flu or as sedative ^[41][42][24,39], while in Turkey the infusion is used as a generic product which is good for health ^[43][127].

The borage or starflower (Borago officinalis L.) is an annual herb widely distributed beyond its original habitat in the Euro-Mediterranean region as a wild weed or cultivated as a garden plant, a crop vegetable, or for medicinal purposes ^[44][45][128,129]. The flowers are blue and rarely appear white or rose colored. The flowers arise along scorpioid cymes to form large floral displays. The flowering period is from early spring to summer (in some Italian regions even in winter), depending on the climate ^[46][130]. Borage flowers (14 papers, three countries) are used in salads, fritters, and soups or as a vinegar aromatizer. Aldehydes and terpenes are the major chemical classes among the aromatic volatile components of the B. officinalis flowers ^[47][131]. Borage flowers are rich in fatty acids (mainly α-linolenic, stearidonic, palmitic, linoleic, and γ-linolenic acids), organic acids (mainly malic and levulinic acids), and carotenoids (β-carotene and lutein) ^[48][132]. Borage flowers could therefore be considered as a source of putative antioxidant and antibacterial compounds to improve human health and to be used as a biopreservative in food and cosmetic industries ^[49][133]. The infusion or macerate of borage flowers is used in Italy and Spain for the treatment of colds, bronchitis, sore throats, and gastritis; it is also used as a diuretic and an anti-rheumatic ^[50][51][48,134].

The caper bush or flinders rose (Capparis orientalis Veill; C. spinosa L.) is a deciduous shrub, apparently native to the dry regions of western and central Asia; however, long ago it spread to North and East Africa, Madagascar, Australia, and Oceania ^[52][135]. The branched stems are trailing or ascending. These plants prefer dry heat and intense sunlight. The drought- and salt-tolerant nature of these species allows it to persist in a wide range of habitats, even on nutrient-poor, sandy, and gravelly soils ^[53][136]. The flowers are sweetly fragrant, white and often tinged with pink, with many long violet-colored stamens. The caper bush has been introduced as a specialized culture in some European countries. The flower buds (12 papers, five countries) are consumed salted or pickled as a vegetable condiment and are among the most popular species of aromatic plants grown in the Mediterranean zone. The flower buds are rich in volatile compounds, and cinnamaldehyde and benzaldehyde are the most abundant aldehydes ^[54][137]. Methyl isothiocyanate and dL-limonene are the main aroma-active compounds of the fresh flower buds ^[55][138]. The amounts of the flavonoids kaempferol and quercetin 3-O-glucoside, quercetin 3-O-glucoside-7-O-rhamnoside, and rutin in the caper’s buds are remarkable ^[56][139]. A caper decoction is used in Tunisia as antidiabetic and diuretic ^[57][63], while in Turkey it is used as a treatment for hemorrhoids and gastric ulcers ^[58][23].

The dandelion (Taraxacum officinale Weber and F.H. Wigg.) is a herbaceous perennial plant native to Europe and Asia that can thrive in a wide range of conditions; in fact, it can be found on all the continents, except for Antarctica ^[59][140]. The leaves are arranged in a basal rosette, yellow to orange flowers are grouped in solitary capitula at the top of the scape. Blooming occurs from spring until autumn, depending on the plant’s location. Dandelion flowers (eight papers, four countries) are used in popular traditions for the preparation of salads, fritters, risotto, jam, and tea or as a seasoning. Dandelion flowers are rich in phytochemicals, such as carotenoids, flavonoids, phenolic acids, and terpenes, with the resulting sesquiterpene lactones and caffeoylquinic acid derivatives being the most abundant secondary metabolites, followed by flavonoids ^[60][141]. The antioxidant and cytotoxic properties can in part be attributed to the presence of luteolin and luteolin 7-glucoside ^[61][62][142,143]. Dandelion flowers (T. officinale, as well as the related T. campylodes G.E. Haglund) are used in the folk phytotherapy of the Mediterranean basin in infusion for the treatment of respiratory or urogenital diseases ^[42][63][39,44] or topically for healing wounds ^[64][65][28,104].

White and red clovers (Trifolium repens L. and T. pratense L., respectively) are a globally distributed species of perennial herbs which are common in most grassy areas or are cultivated as a forage crop. The flowers are whitish (T. repens) or dark pink with a paler base (T. pratense); they are produced in a dense inflorescence and are mostly visited by bumblebees ^[66][144]. Blooming occurs from early spring until late summer, depending on the climate. Clovers flowers (11 papers, three countries) are used in salads, cakes, fritters, and soups or for tea preparation. Trifolium extracts have a high total content of polyphenols as well as a high antioxidant potential ^[67][145]. T. repens extract contains a high level of rutin and quercetin, while T. pratense extract contains luteolin and kaempferol; these data support the use of clover flowers as healthy food ingredients ^[68][146]. T. pratense flowers are used in Italy and Turkey in the treatment of stomach diseases, coughs, and menopause disorders ^[69][70][71][29,106,147].

The sweet or English pansy (Viola odorata L.) is a herbaceous perennial plant native to the south and parts of western Europe and is now widely naturalized. V. odorata is a rosette-forming plant with long, freely-rooting stolones. The flowers are dark violet or white and sweet-scented and appear in spring. Sweet pansies have been cultivated for cosmetics and medicine in Europe since antiquity ^[72][148]. The sweet pansy flowers (nine papers, four countries) are consumed in salads or are used to prepare sweets, fritters, and liqueurs. Flavonol glycosides, principally derivatives of kaempferol, are among the major chemical constituents of the sweet pansy, and the presence of high amounts of free sugars and mucillage is reported ^[73][149]. The sweet pansy flower infusion is commonly used in Italy against coughs and as a diaphoretic, a diuretic, or a mild laxative or as cold adjuvant ^[74][75][150,151].

The wild pansy or heartsease (Viola tricolor L.) is a biennial or a short-lived perennial which is native to Europe and Asia. The flowers can be purple, blue, yellow, or white and appear from spring to late summer. Wild pansy flowers are usually added to salads in Italy and Bosnia-Herzegovina (four papers, three countries). V. tricolor flowers show high contents of anthocyanidins and flavonoids; the highest cyanidin-3-glucoside content is present in the violet flower, while the white and yellow pansies showed the highest rutin content ^[76][152]. The V. tricolor flower infusion is taken orally in the Italian traditional pharmacopoeia for the treatment of coughs ^[69][29].

The corn poppy (Papaver rhoeas L.) is a cosmopolitan annual herbaceous plant. Before anthesis, the elliptical flower buds are pendulous, but when it occurs, they become erect and the two sepals underneath drop, allowing the red petals to expand. This species has been associated with agriculture in the Old World since early times, and its diffusion is linked to the cultivation of cereals ^[46][130]. Corn poppy flowers (five papers, three countries) are used raw or cooked in the preparation of sorbet, patties, or as a stew or egg–vegetable dish. Various phytochemical components have been identified in corn poppy petals (e.g., alkaloids, flavonoids, vitamins, anthocyanins, and essential oils); the petals are rich in anthocyanins, which are responsible for the red color ^[77][153]. The most represented anthocyanins in the extracts of P. rhoeas were found to be delphinidin-3-O-glucoside, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, petunidin-3-O-glucoside, petunidin-3- acetylglucoside, and delphinidin-3-p-coumaroylglucoside ^[78][154]. Different parts of the plant (the roots, stems, leaves, and petals) exhibited several biological activities, including antidepressant, antimicrobial, antioxidant, antiulcerogenic, and cytotoxic activities ^[79][155]. The P. rhoeas flowers are widely used in the Mediterranean basin as a sedative and for the treatment of various ailments, such as respiratory and gastro-intestinal system ailments, diabetes, and measles, and topically as a vulnerary ^[80][81][82][156,157,158].

The pot marigold (Calendula officinalis L.) is an annual or short-lived perennial herb whose origin is unknown, but it is probably native to southern Europe and the eastern Mediterranean area. It is a weed that grows in cultivated fields, along roadsides, and in disturbed sites on a variety of soil types ^[83][159]. The marigold is widely cultivated as an ornamental and for its therapeutic properties. The daisy-like inflorescences are typically bright orange or yellow and held on thick stems. The marigold blooms over a long period where the conditions are suitable. The C. officinalis flowers (as well as the related C. arvensis L.) are widely used in Italy and Bosnia-Herzegovina in salads or as a condiment. The main constituents of the marigold flowers include steroids, terpenoids, triterpenoids, flavonoids, phenolic acids, and carotenes ^[84][85][160,161]. Faradiol, caffeic acid, rutin, and chlorogenic acid isolated from C. officinalis exhibit biological activity ^[86][162]. Pharmacological studies have shown that the marigold exhibits antibacterial, antiviral, anti-inflammatory, antioxidant, hypoglycemic, hypolipidemic, and wound healing properties ^[87][88][89][163,164,165]. In the folk phytotherapy, both C. officinalis and C. arvensis are used as remedies for a wide range of diseases. The C. arvensis flower infusion is used orally in Spain as an emmenagogue ^[54][137], in Greece as an antispasmodic ^[90][166], and in Italy as an antispasmodic and a diuretic ^[91][167]. The C. officinalis flower infusion is used orally in Italy for urinary tract disorders, gastrointestinal pains, and dysmenorrhea ^[64][92][28,168] and in Croatia for kidney disorders, hepatitis, and stomach ulcers ^[93][169]. Both marigolds are used topically in the Mediterranean basin for skin disease treatment (wounds, burns, erythema, rheumatic pains, varicose veins, corns, warts, etc.) (e.g., ^[64][94][28,97]).

Finally, the use of large-leaved linden (T. platyphyllos Scop.) flowers for tea and liqueur preparation is worthy of note (five papers, four countries). This species is native to central and southern Europe and is widely planted throughout the temperate world as an ornamental tree ^[95][170]. The very fragrant, yellowish-white flowers are arranged in drooping, cymose clusters and appear in late spring to early summer. A detailed phytochemical profile of T. platyphyllos inflorescences revealed the presence of flavonoids, mainly quercetin glycosides (rutin, hyperosid, quercitrin, quercetin-3,7-di-O-rhamnoside, quercetin-rhamno-xyloside, and quercetin-3-O-gluco-7-O-rhamnoside) and kaempferol glycosides (astragalin, tilirosid, kaempferol- 3-O-gluco-7-O-rhamnoside, and kaempferol-3,7-di-O-rhamnoside) ^[96][171]. A high content of oligomeric and polymeric procyanidins, mainly composed of catechin and epicatechin building blocks such as prodelphinidin C and procyanidin B4, has been identified ^[97][172]. The T. platyphyllos flower infusion is widely used in the folk phytotherapy of the Mediterranean basin for its sedative properties but also to treat coughs, sore throats, and bronchitis and as a febrifuge or galactagogue ^{[98][99][100]}[173,174,175].