Morelloid Clade Research Articles

A revision of the South American species of the Morelloid clade (Solanum L., Solanaceae).

The Morelloid clade, also known as the black nightshades or "Maurella" (Morella), is one of the 10 major clades within the mega-diverse genus Solanum L. The clade is most diverse 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 vary from herbs to short-lived perennials to perennial shrubs that are distinctly woody at the base, they have small mostly 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 clades in Solanum. Here we provide the last in a three-part series of monographic treatments of the morelloid solanums (see PhytoKeys Vols. 106, 125), treating the 62 species occurring in South America. This region is by far the most diverse in the clade, both in terms of species number and morphological diversity. We provide complete synonymy, nomenclatural details, including lecto- and neotypifications where needed, common names and uses, morphological descriptions, illustrations to aid identification both in herbaria and in the field, and distribution maps for all native, non-cultivated species. We include a key to all species, a synoptic character list for the species treated here and links to synoptic online keys for all species of the Morelloid clade. Preliminary conservation assessments following IUCN guidelines are also provided for all native species.

The Morelloid clade of Solanum L. (Solanaceae) in Argentina: nomenclatural changes, three new species and an updated key to all taxa.

Since the publication of the Solanaceae treatment in “Flora Argentina” in 2013 exploration in the country and resolution of outstanding nomenclatural and circumscription issues has resulted in a number of changes to the species of the Morelloid clade of Solanum L. (Solanaceae) for Argentina. Here we describe three new species: Solanum hunzikeri Chiarini & Cantero, sp. nov., from wet high elevation areas in Argentina (Catamarca, Salta and Tucumán) and Bolivia (Chuquisaca and Tarija), S. marmoratum Barboza & S. Knapp, sp. nov., from central Argentina in Catamarca, La Pampa, La Rioja, San Juan and San Luis, and S. tiinae Barboza & S. Knapp, sp. nov., from the mountains of Jujuy, La Rioja, Salta and Tucumán. We provide descriptions, illustrations and distribution maps for all new taxa. A table of nomenclatural changes and additional taxa now known to occur in Argentina summarizes additions and changes since the “Flora Argentina”. We also provide an updated key, including all new taxa for the country, to facilitate identification and further exploration.

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

The Morelloid Clade, also known as the black nightshades or “Maurella” (Morella), is one of the 10 major clades within the mega-diverse genus Solanum L. 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 in Solanum. 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.

A new black nightshade (Morelloid clade, Solanum, Solanaceae) from the caatinga biome of north-eastern Brazil with a key to Brazilian morelloids.

Solanumcaatingaesp. nov. is described from the arid caatinga biome of north-eastern Brazil. It is known from only a few specimens, but these were found amongst the many sheets of the widespread circumtropical weed S.americanum Mill.; it is possible that more will be found once its distinct nature has been recognised. It differs from S.americanum and all other herbaceous black nightshades known in Brazil, in its combination of glandular pubescence and shiny black fruit with small spreading sepals. The description of S.caatingae brings the number of morelloid solanums in Brazil to seven and a key is provided for their identification.

A revision of the Old World Black Nightshades (Morelloid clade of Solanum L., Solanaceae).

The Morelloid clade, also known as the black nightshades or “Maurella” (Morella), is one of the 10 major clades within Solanum L. The pantropical clade consists of 75 currently recognised non-spiny herbaceous and suffrutescent species with simple or branched hairs with or without glandular tips, with a centre of distribution in the tropical Andes. A secondary centre of diversity is found in Africa, where a set of mainly polyploid taxa occur. A yet smaller set of species is found in Australasia and Europe, including Solanum nigrum L., the type of the genus Solanum. Due to the large number of published synonyms, combined with complex morphological variation, our understanding of species limits and diversity in the Morelloid clade has remained poor despite detailed morphological studies carried out in conjunction with breeding experiments. Here we provide the first taxonomic overview since the 19th century of the entire group in the Old World, including Africa, Asia, Australia, Europe and islands of the Pacific. Complete synonymy, morphological descriptions, distribution maps and common names and uses are provided for all 19 species occurring outside the Americas (i.e. Africa, Asia, Australia, Europe and islands of the Pacific). We treat 12 species native to the Old World, as well as 7 taxa that are putatively introduced and/or invasive in the region. The current knowledge of the origin of the polyploid species is summarised. A key to all of the species occurring in the Old World is provided, together with line drawings and colour figures to aid identification both in herbaria and in the field. Preliminary conservation assessments are provided for all species.

Two new non-spiny Solanum (Solanaceae) from the Gran Chaco Americano and a key for the herbaceous glandular-pubescent solanums from the region.

The Gran Chaco Americano is a major savanna woodland system in South America that harbours great plant and animal diversity. Two new herbaceous species of the Morelloid clade of Solanum (largely corresponding to the traditional Solanum section Solanum) are described here from the Bolivian Chaco. Both species are morphologically similar to a group of related species with glandular pubescence and enlarged, foliaceous calyces that includes Solanum atriplicifolium Gillies ex Nees, Solanum nitidibaccatum Bitter, Solanum physalifolium Rusby, Solanum sarrachoides Sendtn. and Solanum tweedianum Hook. Solanum woodii Särkinen & S.Knapp, sp. nov. is unusual in the Morelloid clade in having tapering anthers on short filaments, and is superficially similar to the unrelated Solanum anomalostemon S.Knapp & M.Nee from dry forests in Peru. Solanum michaelis Särkinen & S.Knapp, sp. nov. is distinct in its enlarged calyx with a short tube and long lobes that apparently reflex at fruit maturity. Both new taxa are illustrated, their conservation status assessed, and their distributions mapped. We also provide a key to the glandular-pubescent herbaceous Solanum species of the Chaco vegetation to aid in identification of these taxa.

Heterochromatin and rDNA patterns in Solanum species of the Morelloid and Dulcamaroid clades (Solanaceae)

The heterochromatin distribution and the position of 18-5.8-26S, and 5S rDNA loci were determined in 13 species of Solanum of the Morelloid and Dulcamaroid clades. The CMA/DAPI staining and FISH were employed. Two types of constitutive heterochromatin were determined: CMA+/DAPI− associated to NOR and CMA+/DAPI− distributed as terminal bands. In the Morelloid clade, CMA+/DAPI− bands were found in five species while in the Dulcamaroid clade, only S. angustifidum presented this feature. In the Morelloid clade, two to four 18-5.8-26S rDNA loci occupied terminal positions and two rDNA 5S loci were found with variable positions (terminal, intercalary, and centromeric). In the Dulcamaroid clade, two terminal 18-5.8-26S rDNA loci were detected with the exception of S. salicifolium which possessed four such loci and two to four 5S rDNA loci. Solanum crispum is the only species possessing the 5S in synteny with 18-5.8-26S rDNA loci. Karyotype features chromosome banding pattern as well as the location of ribosomal genes which varied among the species, reflecting the chromosome differentiation and evolutionary divergence. The findings obtained contributed to the development of tools that can be used for establishing chromosomic homeologies among species and hence to clarify their taxonomic relationships.

True Black nightshades: Phylogeny and delimitation of the Morelloid clade of Solanum

AbstractThe Morelloid clade of Solanum, also known as the black nightshades or Maurella (Morella), is one of the 10 major clades within Solanum. The pantropical clade consists of ca. 76 non‐spiny herbaceous and suffrutescent species with simple or branched hairs with or without glandular tips, with a centre of distribution in the tropical Andes. Although the core members of the clade have long been recognised, complete circumscription of the Morelloid clade has remained elusive. Here we provide the first detailed molecular study of the clade. Plastid (trnT‐F intergenic spacers), nuclear ribosomal ITS, and low‐copy nuclear (waxy) data show three of the four previously unplaced taxa loosely associated with the Morelloids to be placed outside (S. anomalostemon, S. valdiviense, S. reductum), whilst S. salicifolium, a species previously associated with the Dulcamaroid clade, is found to be nested within the group. Four monophyletic groups within the Morelloids can be recognised: (1) Black nightshade clade, including all members of S. sect. Solanum, S. sect. Campanulisolanum, branched‐haired taxa, S. salicifolium, and S. triflorum; (2) Episarcophyllum clade, including most members of S. sect. Episarcophyllum; (3) Chamaesarachidium clade, including members of S. sect. Chamaesarachidium; and (4) Radicans clade, including four species from S. sect. Parasolanum. Incongruence between nuclear and plastid gene trees is discussed in relation to known ploidy level variation across the Morelloid clade, especially the African species often referred to as the S. nigrum complex. A new, revised circumscription of the Morelloid clade is provided together with morphological characterisations of the monophyletic clades recovered within it. A preliminary checklist of accepted names for Morelloids is also presented.

Two new non-spiny Solanum species from the Bolivian Andes (Morelloid Clade).

Two new Bolivian species are described from the Morelloid clade of Solanum (section Solanum in the traditional sense). Solanum alliariifolium M.Nee & Särkinen, sp. nov. is found in montane forests between 1,900 and 3,200 m and is morphologically most similar to Solanum leptocaulon Van Heurck & Müll.Arg., also from montane forests in southern Peru and Bolivia. Solanum rhizomatum Särkinen & M.Nee, sp. nov. is found in seasonally dry forests and matorral vegetation in lower elevations between 1,300 and 2,900 m and is most similar to Solanum pygmaeum Cav., a species native to sub-tropical Argentina but introduced in subtropical and temperate areas worldwide.

Four new non-spiny Solanum (Solanaceae) species from South America.

Four new species of “non-spiny” Solanum from South America are described. Solanum longifilamentum Särkinen & P.Gonzáles, sp. nov. (Morelloid clade) is widespread from Ecuador to Bolivia and is most similar to Solanum macrotonum Dunal from Central and northern South America. Solanum antisuyo Särkinen & S.Knapp, sp. nov. (Morelloid clade) is found on the eastern Andean slopes in Ecuador, Peru and Bolivia and is most similar to the widespread lower elevation species Solanum polytrichostylum Bitter. Solanum arenicola Särkinen & P.Gonzáles, sp. nov. (Morelloid clade) is found in low elevation habitats on the eastern Andean slopes and in Amazonia of Peru and Bolivia and is most similar to the higher elevation species Solanum aloysiifolium Dunal of Bolivia and Argentina. Solanum mariae Särkinen & S.Knapp, sp. nov. (Potato clade) is endemic to Cajamarca Department in Peru, and is most similar to the widespread Solanum caripense Dunal. Complete descriptions, distributions and preliminary conservation assessments of all new species are given.

Distribution models and species discovery: the story of a new Solanum species from the Peruvian Andes

A new species of Solanum sect. Solanum from Peru is described here. Solanum pseudoamericanum Särkinen, Gonzáles & S.Knapp sp. nov. is a member of the Morelloid clade of Solanum, and is characterized by the combination of mostly forked inflorescences, flowers with small stamens 2.5 mm long including the filament, and strongly exerted styles with capitate stigmas. The species was first thought to be restricted to the seasonally dry tropical forests of southern Peru along the dry valleys of Río Pampas and Río Apurímac. Results from species distribution modelling (SDM) analysis with climatic predictors identified further potential suitable habitat areas in northern and central Peru. These areas were visited during field work in 2013. A total of 17 new populations across the predicted distribution were discovered using the model-based sampling method, and five further collections were identified amongst herbarium loans. Although still endemic to Peru, Solanum pseudoamericanum is now known from across northern, central and southern Peru. Our study demonstrates the usefulness of SDM for predicting new occurrences of rare plants, especially in the Andes where collection densities are still low in many areas and where many new species remain to be discovered.

Karyotypes of South American species of the Morelloid and Dulcamaroid clades (Solanum, Solanaceae)

A karyotypic study on South American representatives of the Morelloid and Dulcamaroid clades of Solanum was conducted to contribute to a better understanding of their relationships. Mitotic chromosomes of 26 species were examined (13 of which were previously unknown). All taxa presented 2n = 2x = 24 and had small chromosomes (less than 4 μm long) with the exception of S. crispum. Most species displayed symmetrical karyotypes, being 78% and 69% m, 19% and 25% sm and 3% and 6% st for the Morelloid and Dulcamaroid clades, respectively. Solanum crispum (Dulcamaroid clade) was unique by having mostly sm chromosomes and S. sinuatirecurvum (Morelloid clade) stood out with four st pairs and an exclusive pair of satellites in long arms. Solanum tripartitum was the sole entity exhibiting an sm pair with satellites. Most examined species of these clades resulted karyologically indistinguishable, based on conventionally stained mitotic chromosomes. Molecular analyses are needed to gain a better knowledge of the possible karyoevolutionary trends of both clades.

Predicting Plastid Marker Variation: Can Complete Plastid Genomes from Closely Related Species Help?

Rapidly evolving non-coding plastid regions (NCPs) are currently widely used in evolutionary biology especially in plant systematic studies where NCPs have become one of the most commonly used tools in clarifying species relationships. Currently, the generally small amount of sequence variation provided by NCPs compared to nuclear regions makes plastid phylogeny reconstruction challenging at the species-level, especially so in species rich clades such as Solanum with c. 1,200 species. Previous studies have established that the set of most highly variable NCPs vary between major plant families, and here we explore whether this variation extends beyond family level to genera and major clades within genera. Using full plastome data, we identify the most highly variable plastid markers in the Potato clade of Solanum. We then compare sequence variation between the Potato and the closely related Morelloid clade. Results show that whilst a narrow set of NCPs show consistently high variation, levels of sequence variation in most NCPs differ greatly between the two closely related clades. The high variation detected between closely related groups implies that repeated screening studies will be needed for individual projects despite the potential availability of results from closely related taxa, and indicates a narrower applicability of family-specific screening studies than previously thought.