Solanum chenopodioides
2n=2x=24 (Baylis 1958; Soria and Heiser 1961 [as S. gracile]; Heiser et al. 1965 [as S. gracile]; Venkateswarlu and Rao 1972; Henderson 1974 [as S. gracilius]; Randell and Symon 1976; Edmonds 1972, 1977, 1982, 1983; 1984a [as S. sublobatum]; Moscone 1992; Jacoby and Labuschagne 2006; Moyetta et al. 2013).
Solanum chenopodioides is native to southern South America (see Barboza et al. 2013), but introduced globally in temperate and subtropical areas. It grows in humid, disturbed areas between rocks, along water sources and roads, and in cultivated lands, common in areas with human disturbance; between sea level and 1,900 (-2,500) m elevation.
Old World: Australia: whitetip nightshade (Symon 1981; Edmonds and Chweya 1997); New Zealand: velvety nightshade (Webb et al. 1988; Edmonds and Chweya 1997); South Africa: nastergal; United Kingdom: tall nightshade (Stace 2010).
Uses. South Africa. leaves used as spinach (Edmonds and Chweya 1997); berries locally used for making jam (Viljoen 2011).
Preliminary conservation status (IUCN 2016). Solanum chenopodioides is an extremely widespread cosmopolitan weed, and can be assessed as LC (Least Concern; Table 7). When only the putatively native South American distribution is considered, S. chenopodioides still has a very large EOO of 2,279,138 km2 and remains LC.
From Sarkinen et al. 2018 (https://phytokeys.pensoft.net/article/21991/): Solanum chenopodioides can be distinguished from most of the other morelloids occurring in the Old World based on its narrowly lanceolate leaves with grey indumentum, inflorescences with ca. 3-7 flowers tightly congested near the tip of the peduncle, the stellate corollas that are deeply lobed to the base and usually with a dark purple or black central star and anthers that are usually more than 2 mm and up to 2.8 mm long. In fruit, the pedicels and proximal portion of the peduncle are strongly reflexed and the berries are not at all shiny. Solanum retroflexum has similar matte black berries, but has rhomboid leaves, less deeply divided corollas, shorter anthers and the calyx lobes are strongly reflexed in fruit. Solanum chenopodioides could also potentially be confused with the more common S. nigrum, especially in Europe, but differs from that species in its terete stems, matte black fruits on short strongly reflexed pedicels, and its smaller seeds (1.2 mm long versus 2 mm long).
Solanum chenopodioides has a scattered distribution in the Old World, but it seems to be spreading, perhaps related to climate change and/or increased habitat alteration (Martínez Labarga et al. 2017).
This diploid species possibly contributed its genome to the tetraploid S. retroflexum and hexaploid S. opacum. Jacoby and Labuschagne (2006) reported that crosses made between S. chenopodioides and S. retroflexum were much more successful than between S. americanum and S. retroflexum. This relationship was also confirmed by arbitrary-amplified dominant markers (Jacoby et al. 2003; Poczai and Hyvönen 2011) and by whole genome DArT analysis by van der Walt et al. (2008).
Morton (1976) thought the locality on the type specimen of S. chenopodioides Lam. as “Mauritius” was in error, because the species was a New World taxon in his concept. Morton suggested that the Commerson material on which the name was based was actually from Argentina, but that the localities had been mixed up. This may be true, because there is much material collected by Commerson from Argentina and Uruguay, but S. chenopodioides also occurs on Mauritius as an introduced weed, and we are hence reluctant to suggest the locality is an error.
In the protologue (Roemer and Schultes 1819: 593) of S. besseri both the name and description are attributed to Johann Anton Weinmann (”Weinm. in litt.”) but no specimens or collections are cited. The description is of a plant with subumbellate inflorescences, black fruits, and that comes from America, meaning that in the absence of a type specimen it is difficult to determine the identity of this species. Later Weinmann (1824) published a list of plants from St. Petersburg in which he lists ”S. besserianum” (a nomen nudum with no description) that is probably the same plant, stating it is from “America” and equating it with “S. cestrifolium Jacq.?” (see Doubtful names). Dunal (1852) made a detailed description of S. besseri and put S. americanum in synonymy with it. His description was based on a specimen he saw in “herb. DC” and living plants. In the absence of any original material for this name, we neotypify it here with the specimen in G-DC (G00144198) used by Dunal (1852) and labelled “Solanum besseri” in his hand. The specimen matches his detailed description exactly, and it is not in conflict with the original description (Roemer and Schultes 1819). We do this in order to stabilise the identity of this name so it does not further disrupt names in this group (e.g., see discussions of S. memphiticum and S. villosum).
In the protologue of S. isabellei Dunal (1852) cited specimens in G-DC (Isabelle s.n.) and P (Gay s.n., 1828); we have selected the collection Isabelle s.n. (G00145645) as the lectotype because it is well represented by duplicates in other herbaria. He cited various sheets of plants collected by Philibert Commerson in Uruguay and Argentina as material for his new names S. chenopodiifolium, S. gracile and S. gracile var. microphyllum. There are many Commerson collections corresponding to S. chenopodioides in P, none of which we are treating as strict duplicates; although they have similar morphologies, they all have slightly different collecting localities and labels. Conrad V. Morton (1976) lectotypified S. gracile var. microphyllum by citing his photograph (Morton neg. 8207) of specimens in P, and we have matched this to the individual sheet and add the barcode here as a second step lectotypification. We have selected another of the Commerson sheets in P that is annotated by Dunal as “S. chenopodiifolium” as the lectotype of that name.
Solanum gracile was incorrectly typified by D’Arcy (1974a) on “Hort. Monsp. 1831 (MPU)”, but Dunal did not cite herbarium material from Montpellier, he only cited living material from there (“v.v.”) along with herbarium material from G-DC and P (“v.s. in h. DC h. Mus Paris. et v.v.”). Any herbarium material prepared from such living specimens would be a neotype, but that is inappropriate while syntypes still exist. Henderson (1974) cited as lectotype for S. gracile a sheet in G-DC without citing a collector, but he did cite a microfiche number (IDC 800-61.2063:III.7) that corresponds to Gaudichaud 520, the material cited in the protologue. His lectotypifcation is effective, because he cited a single collection in a single herbarium (G-DC, G003144391); duplicates in G and P are isolectotypes. Morton (1976) later superfluously lectotypified S. gracile with Commerson material at P, citing his photograph (Morton neg. 8206); this specimen (P00384083) is not a type, although it was cited as the lectotype by Barboza et al. (2013).