Solanum evolvuloides is known only from the southeastern part of Bahia state (Fig. 3 in Giacomin & Stehmann 2012), Brazil, occurring in the transition zone between deciduous forests and xeric formations of shrubby Caatinga (as defined by Velloso et al. 2002). Ecology. Solanum evolvuloideswas recently recollected by Giacomin in the municipality of Jequié in a typical shrubby Caatinga formation, that is associated in this region with large granitic outcrops. The occurrence on the banks of the Rio de Contas near the city of Itacaré [Jardim, J.G. 1843 (CEPEC)] might be an occasional case of water dispersal by the river, which arises in a xeric environment near the center of the state in the Caatinga biome. Despite having been found in environments with marked seasonality, the species is apparently not annual, as evidenced by the woody stem bases.
Solanum evolvuloides is a member of section Gonatotrichum (part of hte Brevantherum clade).
Solanum evolvuloides is similar to Solanum turneroides Chodatand they are the only species within the section presenting strong heterandry, with one stamen with a filament much longer than the other four. Sometimes Solanum parcistrigosum Bitterand Solanum hoffmannseggii Sendtner, species that also resemble Solanum evolvuloides, are weakly heterandrous but they both have smaller flowers (corolla with < 1.5 cm in diameter) and stamens, and can be easily distinguished from Solanum evolvuloides by the glandular indument observed in the calyx and stems of the latter species. This character can be also used to separate Solanum evolvuloides from Solanum turneroides. These two speciesare also not sympatric, in Brazil Solanum turneroides is found only in the states of Mato Grosso do Sul and São Paulo, whereas Solanum evolvuloides occurs only in Bahia. Solanum turneroides has an indument composed of unbranched eglandular hairs mainly with one-celled appressed hairs on the calyces, leaves and stems, associated with two-celled hairs that are typically geniculate (bent at a 90° angle) between the first and second cell. It is also a more robust shrub with chartaceous leaves, in contrast to the more membranaceous leaves of Solanum evolvuloides.
Within the section, glandular hairs are commonly found on the leaves of Solanum adscendens Sendtner but in this species, the hairs are much smaller (up to 0.1 mm, barely visible in dried material) than those of Solanum evolvuloides, have glands composed of more than one cell, and are associated with several erect eglandular hairs. The hairs of Solanum evolvuloides, perhaps the most distinctive characteristic of the species, are up to 0.5 mm long, are stalked, have unicellular glands, and are not commonly found on the leaves.
The heterandry found in Solanum evolvuloides is not a common feature within Solanum, and its evolution had been focus of recent studies, using morphological or molecular data (Lester et al. 1999, Bohs et al. 2007). Both cited works conclude that this character evolved several times independently within the genus. Within the Brevantherum clade (sensu Weese and Bohs 2007), only the two species of sect. Gonatotrichum cited above are known to be strongly heterandrous. The species do not present strong enantiostyly, but in both cases a deflection on the style apex is observed (see Fig. 2A), that might function to receive pollen from a bee’s abdomen, as pointed out in other studies of heterandrous and enantiostylous Solanum species (e.g. Vallejo-Marín 2009).
For references cited here please see Giacomin, LL.. & J.R. Stehmann 2012. A new heterandrous species of Solanum section Gonatotrichum Bitter (Solanaceae) from Bahia, Brazil. PhytoKeys 7: 1–9
Endangered (EN) B1 a, b (i, ii, iii, iv). Solanum evolvuloides is known from only two localities, where the landscape has been strongly modified in the last decades due to the expansion of urban centers and extensive farming. The region has been focus of several surveys undertaken by the CEPEC group, in association with the New York Botanical Garden; despite this, only a few collections of this species have been made. Although one collection was made in a very disturbed area (Jardim 1843), the most recent collection is from a well-preserved forest fragment, and the species was not found in surrounding areas. There are no collections from within conservation units.