Solanaceae (), commonly known as the nightshades, is a family of flowering plants in the order Solanales. The family contains approximately 2,700 species, several of which are used as agricultural crops, medicinal plants, and ornamental plants. Many members of the family have high alkaloid contents, making some highly toxic, but many—such as tomatoes, potatoes, eggplants and peppers—are commonly used in food around the world.
Originating in South America, Solanaceae now inhabit every continent on Earth with the sole exception of Antarctica. After the K–Pg extinction event they rapidly diversified and have adapted to live in deserts, tundras, rainforests, plains, and highlands, and taken on wide range of forms including trees, vines, shrubs, and epiphytes. Nearly 80% of all nightshades are included in the subfamily Solanoideae, most of which are members of the type genus Solanum. Most taxonomists recognize six other subfamilies: Cestroideae, Goetzeoideae, Nicotianoideae, Petunioideae, Schizanthoideae, and Schwenkioideae, although nightshade taxonomy is still controversial. The genus Duckeodendron is sometimes placed in its own subfamily, Duckeodendroideae.
The high alkaloid content in some species has made them valuable for recreational, medicinal, and culinary use. The tobacco plant has been used for centuries as a recreational drug because of its high nicotine content. The tropanes in Atropa bella-donna can have pain-killing, relaxing, or psychedelic effects, making it a popular plant in alternative medicine, as well as one of the most toxic plants in the world. The presence of capsaicin in Capsicum species gives their fruits their signature pungency, which are used to make most spicy food products sold today.
Other nightshades are known for their beauty, such as the long, slender flowers of Brugmansia, the various colors of Petunia, or the spotted and speckled varieties of Schizanthus.
Etymology The name "Solanaceae" comes from Solanum, the type genus of the family, + -aceae, the suffix for plant family names. The etymology of the word solanum is unclear. The name probably comes from a perceived resemblance of certain species' flowers to the sun (sol in Latin) and its rays. At least one species of Solanum is known as the "sunberry". Alternatively, the name could originate from the Latin verb solare, meaning "to soothe", presumably referring to the soothing pharmacological properties of some of the psychoactive species of the family.
The common name "nightshade" developed directly from Middle English nyght-shade, originating from the Old English word nihtscada ( "shade of night"), cognate with Germanic words such as German nachtschatten and Dutch nachtschade. The reason for these names is unknown, but could have been a reference to the appearance of the fruits.
Description
Nightshades can take the form of herbs, shrubs, trees, vines and lianas, and sometimes epiphytes. They can be annuals, biennials, or perennials, upright or decumbent. Some have subterranean tubers. They do not have laticifers, nor latex, nor coloured saps. They can have a basal or terminal group of leaves or neither of these types. The leaves are generally alternate or alternate to opposed (that is, alternate at the base of the plant and opposed towards the inflorescence). The leaves can be herbaceous, leathery, or transformed into spines. The leaves are generally petiolate or subsessile, rarely sessile. They are frequently inodorous, but some are aromatic or fetid. The foliar lamina can be either simple or compound, and the latter can be either pinnatifid or ternate. The leaves have reticulated venation and lack a basal meristem. The laminae are generally dorsiventral and lack secretory cavities. The stomata are generally confined to one of a leaf's two sides; they are rarely found on both sides.
The flowers are generally hermaphrodites, although some are monoecious, andromonoecious, or dioecious species (such as some Solanum or Symonanthus). They are most commonly pollinated by insects. The flowers can be solitary or grouped into terminal, cymose, or axillary inflorescences. The flowers are medium-sized, fragrant (Nicotiana), fetid (Anthocercis), or inodorous. The flowers are usually actinomorphic, slightly zygomorphic, or markedly zygomorphic (for example, in flowers with a bilabial corolla in Schizanthus species). The irregularities in symmetry can be due to the androecium, to the perianth, or both at the same time. In the great majority of species, the flowers have a differentiated perianth with a calyx and corolla (with five sepals and five petals, respectively) an androecium with five stamens and two carpels forming a gynoecium with a superior ovary (they are therefore referred to as pentamers and tetracyclic). The stamens are epipetalous and are typically present in multiples of four or five, most commonly four or eight. They usually have a hypogynous disk. The calyx is gamosepalous (as the sepals are joined forming a tube), with the (4)5(6) segments equal, it has five lobes, with the lobes shorter than the tube, it is persistent and often accrescent. The corolla usually has five petals that are also joined forming a tube. Flower shapes are typically rotate (wheel-shaped, spreading in one plane, with a short tube) or tubular (elongated cylindrical tube), campanulated, or funnel-shaped.
The androecium has (2)(4)5(6) free stamens within its opposite sepals (they alternate with the petals). They are usually fertile or, in some cases (for example in Salpiglossideae) they have staminodes. In the latter case, there is usually either one staminode (Salpiglossis) or three (Schizanthus). The anthers touch on their upper end forming a ring, or they are completely free, dorsifixed, or basifixed with poricide dehiscence or through small longitudinal cracks. The stamen's filament can be filiform or flat. The stamens can be inserted inside the coralline tube or exserted. The plants demonstrate simultaneous microsporogenesis, the microspores are tetrad, tetrahedral, or isobilateral. The pollen grains are bicellular at the moment of dehiscence, usually open and angular.
The gynoecium is bicarpelar (rarely three- or five-locular) with a superior ovary and two locules, which may be secondarily divided by false septa, as is the case for Nicandreae and Datureae. The gynoecium is located in an oblique position relative to the flower's median plane. They have one style and one stigma; the latter is simple or bilobate. Each locule has one to 50 ovules that are anatropous or hemianatropous with axillar placentation. The development of the embryo sack can be the same as for Polygonum or Allium species. The embryo sack's nuclear poles become fused before fertilization. The three antipodes are usually ephemeral or persistent as in the case of Atropa. The fruit can be a berry as in the case of the tomato or wolfberry, or a dehiscent capsule as in Datura, or a drupe. The fruit has axial placentation. The capsules are normally septicidal or rarely loculicidal or valvate. The seeds are usually endospermic, oily (rarely starchy), and without obvious hairs. The seeds of most Solanaceae are round and flat, about in diameter. The embryo can be straight or curved, and has two cotyledons. Most species in the Solanaceae have 2n=24 chromosomes, but the number may be a higher multiple of 12 due to polyploidy. Wild potatoes, of which there are about 200, are predominantly diploid (2 × 12 = 24 chromosomes), but triploid (3 × 12 = 36 chromosomes), tetraploid (4 × 12 = 48 chromosomes), pentaploid (5 × 12 = 60) and even hexaploid (6 × 12 = 72 chromosome) species or populations exist. The cultivated species Solanum tuberosum has 4 × 12 = 48 chromosomes. Some Capsicum species have 2 × 12 = 24 chromosomes, while others have 26 chromosomes.
Diversity of characteristics Despite the previous description, the Solanaceae exhibit a large morphological variability, even in their reproductive characteristics. Examples of this diversity include:Hunziker, A.T. 1979: South American Solanaceae: a synoptic review. In: D'ARCY, W.G., 1979: The Biology and Taxonomy of the Solanaceae. Linn. Soc. Symp. Ser. 7: p 48-85. Linnean Soc. & Academic Press; London.Balken, J.A. THE PLANT FAMILY SOLANACEAE: FRUITS IN SOLANACEAE The number of carpels that form the gynoecium In general, the Solanaceae have a gynoecium (the female part of the flower) formed of two carpels. However, Melananthus has a monocarpelar gynoecium, there are three or four carpels in Capsicum, three to five in Nicandra, some species of Jaborosa and Trianaea and four carpels in Iochroma umbellatum. The number of locules in the ovary
The number of locules in the ovary is usually the same as the number of carpels. However, some species occur in which the numbers are not the same due to the existence of false septa (internal walls that subdivide each locule), such as in Datura and some members of the Lycieae (the genera Grabowskia and Vassobia). Type of ovules and their number The ovules are generally inverted, folded sharply backwards (anatropous), but some genera have ovules that are rotated at right angles to their stalk (campilotropous) as in Phrodus, Grabowskia or Vassobia), or are partially inverted (hemitropous as in Cestrum, Capsicum, Schizanthus and Lycium). The number of ovules per locule also varies from a few (two pairs in each locule in Grabowskia, one pair in each locule in Lycium) and very occasionally only one ovule is in each locule as for example in Melananthus. The type of fruit The fruits of the great majority of the Solanaceae are berries or capsules (including pyxidia) and less often drupes. Berries are common in the subfamilies Cestroideae, Solanoideae (with the exception of Datura, Oryctus, Grabowskia and the tribe Hyoscyameae) and the tribe Juanulloideae (with the exception of Markea). Capsules are characteristic of the subfamilies Cestroideae (with the exception of Cestrum) and Schizanthoideae, the tribes Salpiglossoideae and Anthocercidoideae, and the genus Datura. The tribe Hyoscyameae has pyxidia. Drupes are typical of the Lycieae tribe and in Iochrominae.Armando T. Hunziker: The Genera of Solanaceae. A.R.G. Gantner Verlag K.G., Ruggell, Liechtenstein 2001.
Taxonomy
One of the first scientific references to Solanaceae was in 1763 in French naturalist Michel Adanson's Familles des Plantes. He did not use a formal name for his taxon, and simply labeled the group as "Les Solanum". He included a total of 10 genera. Adanson is however not considered to be the authority of the family, that title instead being held by French botanist Antoine Laurent de Jussieu, who gave the group a formal scientific name in 1789 in his . Jussieu classified the taxon as an order and used the name "Solaneæ". His order included 19 genera, some of which—such as Verbascum blattaria, Bontia, and Crescentia cujete—are no longer considered members of the family. Some genera Jussieu included within Solanaceae he proposed could belong to Boraginaceae, which he also named in Genera Plantarum; he noted that there was a high degree of similarity between Solanaceae and Boraginaceae, and proposed that they could be considered one order.
Following Jussieu's publication, taxonomists have heavily revised, re-examined, and added to the taxon. "Solaneæ" was reclassified as a family by the 1820s, and began to be called "Solanaceae" by some authors around the 1830s, which became the standard name by 1905 per the ICBN nomenclature rules.