The first revision of ring-gentians (Symbolanthus, Gentianaceae) highlights the broad floral morphological diversity that can be present in neotropical asterid genera. Our research during the last 20 years has revealed that the number of Symbolanthus species is at least 38 (including 9 species soon to be described) and is present from Bolivia in the south to Costa Rica in the north, with outliers on the tepuis in Venezuela and Guyana (on the Guiana Shield) and in the lesser Antilles in the Caribbean. The highest species diversity is known from Peru and Colombia. Many species are local endemics, and one species is only known from lowland white-sand areas in the Amazon.  Their funnel- to salvershaped corollas, up to 12 cm long, present a multitude of sizes, shapes, and coloring patterns, with basic colors from green, white, and yellow to pink and deep magenta, depending on species.  Pollinator information is remarkably poor for such a large-flowered taxon, but herbarium records and new investigations have revealed visits by bats and hummingbirds. The Symbolanthus flowers are unique in the presence of a circular corona and/or staminal pockets where the stamens are inserted in the corolla tube. Corona morphology is highly variable and appears to be possibly linked to size of flowers, with larger more fleshy corollas having thicker more ring-shaped coronas with a potentially stabilizing function in the corolla tube (e.g., S. vasculosus). The diversity in floral characteristics may be adaptations to optimize pollination by specific animal groups. Such potential adaptations are observed in the diversity of basic corolla color and corolla tube size and shape, the shape of the corona, as well as in the symmetry of the whole corolla. The symmetry of Symbolanthus corollas varies between mostly radial (e.g., S. pulcherrimus) to strongly bilateral (e.g., S. solaris, to be described.). The distinct disposition of the petals may force the contact between a pollinator’s body and the reproductive organs in a specific way that affects the efficiency of the deposition and removal of pollen. Additionally, Symbolanthus’ strongly zygomorphic reproductive organs (i.e., the long stamens and style) and long reinforced pedicels suggest primary pollination by vertebrates (i.e., birds and bats). Many species present distinct darker or lighter lines in the mouth and throat of the corolla that may function as nectar guides for insect pollination or for regulating corolla temperature and/or absorption of UV light to prevent degradation of the anthers pollen.  The coronas are hypothesized to provide a secondary barrier to the nectar produced at the base of the ovary, with only animals with narrow, long tongues (i.e., the effective pollinators) getting easy access to nectar. Small arthropods may also get nectar access but do not appear to be efficient pollinators (anthers are generally on long filaments and either exserted or inserted), in fact, they might get trapped at the bottom of the flower. We present here an overview of the floral morphology of Symbolanthus as related to potential pollinators, species diversity, and geographic distribution.