Flora of North America species comparison

Nicotiana longiflora is a relatively rare weed along rivers and in waste places. It could be confused with N. plumbaginifolia, with which it is sympatric along the Gulf Coast, but differs from that species in its much larger flowers and its strongly 10-ribbed calyx. In a vegetative state, the two species are very difficult to distinguish.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera ca. 97, species ca. 2500 (27 genera, 151 species, including 2 hybrids, in the flora).

Solanaceae occur on all continents except Antarctica, but their greatest diversity is in the Neotropics. Their closest relative is the Convolvulaceae, from which they can be distinguished by growth form (when herbaceous vines, not with twining stems), the usually 2-locular ovary with numerous ovules, and the absence of laticifers with milky sap. Members of the Solanaceae exhibit a sympodial growth pattern, resulting in unusual placement of leaves, branches, and flowers (A. Child 1979). The foliage of some Solanaceae is fetid or pungent (reminiscent of rotting potatoes or with a sharp, tomato-like smell). The vegetative portions of most members of the family are poisonous due to the presence of tropane and steroidal alkaloids.

Despite the toxicity of its foliage, many Solanaceae species are of worldwide economic importance, such as tomato (Solanum lycopersicum), eggplant (S. melongena), potato (S. tuberosum), chili and bell peppers (Capsicum spp.), tobacco (Nicotiana tabacum), and Petunia. The family also includes many species of small-scale crop, medicinal, or horticultural importance. The most well known of these in the flora area are tomatillo (Physalis philadelphica), belladonna (Atropa belladonna), goji berry (Lycium barbarum and L. chinense), Chinese lantern plant (Alkekengi officinarum), jimsonweed (Datura spp.), jessamine (Cestrum spp.), and Calibrachoa.

The fruit in the Solanaceae is typically a berry or capsule (with circumscissile dehiscence in Hyoscyamus), but may be hardened and drupaceous in some Lycium. The berry-fruited taxa may have a thick, juicy pericarp, or one that is dry and thin, ultimately shattering into irregular pieces. Many genera have an accrescent calyx. The most enlarged of these may become rigid and spinescent (Hyoscyamus), inflated and almost closed around the berry (Alkekengi, Calliphysalis, Physalis, Quincula), loose and enveloping all (Nicandra) or at least the basal half of the berry (Chamaesaracha), or reflexed or flaring (Jaltomata). The brightly colored, juicy berries of many species are animal dispersed. The inflated, bladderlike calyces in several genera also aid in dispersal (short distance by water or ground level by wind).

The showy flowers of Solanaceae are pollinated by bees, flies, butterflies, moths, or hummingbirds foraging for nectar and/or pollen. Solanum does not produce nectar, and pollen is gathered by vibration (buzz pollination) or manipulation of the anthers. Flowers of Cestrum, Datura, and some Nicotiana emit a strong, sweet fragrance in the evening and are moth-pollinated.

Some Solanaceae grown as ornamentals have escaped and persisted for short periods but have not become established in the flora. Nierembergia hippomanica Miers var. coerulea R. Millan has been collected from disturbed sites in Texas (1958, 1962, 1998), and N. scoparia Sendtner was found along a roadside in Georgia in 1947. Nierembergia Ruiz & Pavon is a South American genus. Brugmansia suaveolens (Humboldt & Bonpland ex Willdenow) Sweet, also native to South America, was found in a ruderal yard (2001) and wooded ravine (1983) in Florida. Brugmansia has been treated as part of Datura, but it can be distinguished from that genus by its woody habit, pendulous flowers, and elongated, spineless fruits.

Since the early 1990s, our understanding of the circumscription of the Solanaceae, as well as phylogenetic relationships within the family, have been clarified using both morphological and molecular characters, particularly chloroplast DNA sequence data (W. G. D’Arcy 1991; A. T. Hunziker 2001; T. R. Martins and T. J. Barkman 2005; R. G. Olmstead and L. Bohs 2007; Olmstead and J. D. Palmer 1991, 1992; Olmstead et al. 1999, 2008; T. Särkinen et al. 2013). Based on molecular data, the family is considered monophyletic with the inclusion of Nolana Linnaeus f., Schizanthus, and Sclerophylax Miers. The subfamilies Solanoideae Burnett and Cestroideae Burnett, traditionally recognized on the basis of morphology alone, have been shown to be nonmonophyletic. Some generic concepts have been revised; changes relevant to the flora area are discussed under the various genera.

(Discussion copyrighted by Flora of North America; reprinted with permission.)