Solanumis one of the world's largest and economically most important plant genera, including 1245 currently accepted species and several major and minor crops (e.g., tomato, potato, brinjal eggplant, scarlet eggplant, Gboma eggplant, lulo, and pepino). Here we provide an overview of the evolution of 25 key morphological traits for the major and minor clades of this giant genus based on stochastic mapping using a well‐sampled recently published phylogeny ofSolanum. The most evolutionarily labile traits (showing >100 transitions across the genus) relate to plant structure (growth form and sympodial unit structure), herbivore defence (glandular trichomes), pollination (corolla shape and colour), and dispersal (fruit colour). Ten further traits show evolutionary lability with 50–100 transitions across the genus (e.g., specialised underground organs, trichome structure, leaf type, inflorescence position and branching, stamen heteromorphism). Our results reveal a number of highly convergent traits inSolanum, including tubers, rhizomes, simple leaves, yellow corollas, heteromorphic anthers, dioecy, and dry fruits, and some unexpected pathways of trait evolution that could be explored in future studies. We show that informally named clades ofSolanumcan be morphologically defined by trait combinations providing a tool for identification and enabling predictive phylogenetic placement of unsampled species.

A bush tomato that has evaded classification by solanologists for decades has been identified and is described as a new species belonging to the Australian “Solanumdioicumgroup” of the Ord Victoria Plain biogeographic region in the monsoon tropics of the Northern Territory. Although now recognised to be andromonoecious,S.plastisexumMartine & McDonnell,sp. nov.exhibits multiple reproductive phenotypes, with solitary perfect flowers, a few staminate flowers or with cymes composed of a basal hermaphrodite and an extended rachis of several to many staminate flowers. When in fruit, the distal rachis may abcise and drop. A member of SolanumsubgenusLeptostemonum,Solanumplastisexumis allied to theS.eburneumSymon species group. Morphometric analyses presented here reveal thatS.plastisexumdiffers statistically from all of its closest relatives includingS.eburneum,S.diversiflorumF. Meull.,S.jobsoniiMartine, J.Cantley & L.M.Lacey,S.succosumA.R.Bean & Albr. andS.watneyiMartine & Frawley in both reproductive and vegetative characters. We present evidence supporting the recognition ofS.plastisexumas a distinctive entity, a description of the species, representative photographs, a map showing the distribution of members of theS.eburneumspecies group and a key to the andromonoeciousSolanumspecies of the Northern Territory of Australia. This new species is apparently labile in its reproductive expression, lending to its epithet, and is a model for the sort of sexual fluidity that is present throughout the plant kingdom.

A new Australian species of functionally dioecious bush tomato of Solanum subgenus Leptostemonum is described. Solanum ossicruentum Martine & J.Cantley, sp. nov., is thought to be allied with members of the problematic “Dioicum Complex” lineage, but differs in its short silvery indumentum, long calyx lobes, larger stature, and an unusual fruit morphology that may represent “trample burr” seed dispersal. The species occurs in a range extending from the eastern Kimberley in Western Australia to far northwestern Northern Territory and has been recognized for decades as a variant of S. dioicum W.Fitzg. Specimens of this species were previously referred to by D.E. Symon and others as Solanum dioicum ‘Tanami.’ Ex situ crossing studies and SEM images of inaperturate pollen grains produced in morphologically hermaphrodite flowers indicate that this taxon is functionally dioecious. The scientific name was chosen with the help of 150 seventh grade life science students from Pennsylvania, USA.

Two species new to Solanum sect. Basarthrum (Bitter) Bitter are described. Solanum perlongistylum G. J. Anderson, Martine, Prohens & Nuez and S. catilliflorum G. J. Anderson, Martine, Prohens & Nuez are narrowly distributed species from southern Peru in the group that includes the Andean domesticate S. muricatum Aiton and are very closely related to the widespread S. caripense Dunal. Solanum catilliflorum bears small, dish-shaped flowers (for which it is named) and is self-compatible and autogamous, with short styles like those that characterize all self-compatible species in this section. It also has a low pollen:ovule ratio, which is characteristic of self-compatible species in the group. On the other hand, the style of the self-incompatible S. perlongistylum is the longest in the group, and its flowers have a higher pollen:ovule ratio. Both species are diploid at n = 12. We hypothesize that these two species may be peripheral isolates from the widespread and variable S. caripense.

The dioecious and andromonoecious Solanum taxa (the “S. dioicum group”) of the Australian Monsoon Tropics have been the subject of phylogenetic and taxonomic study for decades, yet much of their basic biology is still unknown. This is especially true for plant-animal interactions, including the influence of fruit form and calyx morphology on seed dispersal. We combine field/greenhouse observations and specimen-based study with phylogenetic analysis of seven nuclear regions obtained via a microfluidic PCR-based enrichment strategy and high-throughput sequencing, and present the first species-tree hypothesis for the S. dioicum group. Our results suggest that epizoochorous trample burr seed dispersal (strongly linked to calyx accrescence) is far more common among Australian Solanum than previously thought and support the hypothesis that the combination of large fleshy fruits and endozoochorous dispersal represents a reversal in this study group. The general lack of direct evidence related to biotic dispersal (epizoochorous or endozoochorous) may be a function of declines and/or extinctions of vertebrate dispersers. Because of this, some taxa might now rely on secondary dispersal mechanisms (e.g. shakers, tumbleweeds, rafting) as a means to maintain current populations and establish new ones.

A new species of andromonoecious Solanum from the Australian “bush tomato clade” of Solanum subgenus Leptostemonum is described. Solanum watneyi Martine & Frawley, sp. nov. is closely allied with S. eburneum, and is sympatric with it in parts of its range in the Northern Territory. The new species has been recognized as a variant of S. eburneum for decades, at times being referred to by local botanists as Solanum sp. “Bullita” because of its relative abundance in the vicinity of the Bullita Station area of Judbarra/Gregory National Park. Morphometric analyses show that S. watneyi differs statistically from S. eburneum in several key reproductive and vegetative characters and field observations suggest that the two sister species may represent a case of edaphic speciation. We provide morphometric evidence for the novelty of S. watneyi, a complete description, and cite specimens for both species.