A revision of the Morelloid Clade of Solanum L. (Solanaceae) in North and Central America and the Caribbean

Abstract

The Morelloid Clade, also known as the black nightshades or “Maurella” (Morella), is one of the 10 major clades within the mega-diverse genusSolanumL. The clade is most species rich in the central to southern Andes, but species occur around the tropics and subtropics, some extending well into the temperate zone. Plants of the group are herbaceous or short-lived perennials, with small white or purplish white flowers, and small juicy berries. Due to the complex morphological variation and weedy nature of these plants, coupled with the large number of published synonyms (especially for European taxa), our understanding of species limits and diversity in the Morelloid Clade has lagged behind that of other major groups inSolanum. Here we provide the second in a three-part series of revisions of the morelloid solanums treating the species occurring in North and Central America and the Caribbean (for the Old World see “PhytoKeys 106”, the third part will treat species of South America). Synonymy, morphological descriptions, distribution maps, and common names and uses are provided for all 18 species occurring in this region. We treat 10 of these species as native, and eight as putatively naturalised, introduced and/or invasive in the region. We provide complete descriptions with nomenclatural details, including lecto- and neotypifications, for all species. Keys to all species occurring in the whole region and for each area within it (i.e., North America, Central America and Mexico, and the islands of the Caribbean), illustrations to aid identification both in herbaria and in the field, and distribution maps are provided. Preliminary conservation assessments are provided for all species. Details of all specimens examined are provided in three Supplementary materials sections.

Dynamism and context‐dependency in diversification of the megadiverse plant genusSolanum(Solanaceae)

“…1200 currently accepted species are distributed globally across all major temperate and tropical biomes, in habitats from deserts to the rainforest to high elevation grasslands. The genus is one of the most species‐rich in flowering plants (Frodin, 2004), and until recently has only been studied in a piecemeal fashion through revisions of small groups or in local floras (see Knapp et al, 2019 for a summary). Several species of Solanum are economically important on a global scale, with several major agricultural crops ( S. tuberosum L., the potato; S. lycopersicum L., tomato; S. melongena L., eggplant), and the genus also contains locally important fruit crops (e.g., S. muricatum Aiton, pepino; S. quitoense Lam., naranjilla) and medicinal plants (e.g., S. marginatum L.f. and S. aviculare Aiton, sources of steroidal alkaloids).…”

Phylogenomic discordance suggests polytomies along the backbone of the large genusSolanum

“…If such characteristics were present in ancestral Solanum, they could have promoted rapid speciation across the globe, followed by rapid morphological evolution and speciation within areas. The patterns observed here could possibly be the result of three major rapid speciation "pulses" across the evolutionary history of common areas where many of the species are found (Knapp, 2013;Särkinen et al, 2018;Knapp et al, 2019).…”

Value Chain Analysis of Chaya (Mayan Spinach) in Guatemala

“…Like chaya, these crops have also been used since pre-Colombian times in Guatemala (Azurdia 2016;Cagnato 2018). Chipilín is likely native to Mesoamerica (Azurdia 2016), while black nightshades S. americanum and S. nigrescens are wide-ranging species of the Americas (Knapp et al 2019). The reason consumers favor these crops over chaya is not clear from the interviews, since they were also regarded as food of the poor, both are used as medicine, and black nightshade can also be toxic, needing to be boiled for safe consumption (Caceres and Cruz 2019;Jagatheeswari et al 2013;Morton 1994).…”