Sinningia is a genus of flowering perennial herbs in the family Gesneriaceae, which also includes African violets. There are about 65 species of Sinningia, all native to the rain forests of Central and South America, with the greatest concentration of species in Brazil. Sinningia plants are tuberous, meaning they have specialized structures called tubers designed to store nutrients. This allows the plant to grow on cliffs and rocks. Some Sinningia species are also cultivated as houseplants.
Most Sinningia species are pollinated by bees or hummingbirds, and feature large, brightly colored flowers to attract their pollinators. S. brasiliensis is pollinated by bats, and S. tubiflora is pollinated by hawk moths. The flowers of S. tubiflora are white, but very fragrant.
S. speciosa is the most well known of the Sinningia species, and the most popular as a houseplant. Native to Brazil, the plant was first cultivated in 1817, when it was given the scientific name Gloxinia speciosa. Though Gloxinia and Sinningia are now considered two separate genera within the Gesnericeae family, with S. speciosa belonging to the latter, S. speciosa is still commonly called gloxinia or florist's gloxinia. Florist's gloxinia generally refers to hybrids of S. speciosa that differ significantly from the plant as it is found in nature. True Gloxinia species are distinguished from Sinningia in that they have rhizomes, or horizontal stems, rather than tubers.
There is great variety within the Sinningias. Many of the very tiny S. pusilla plants could fit inside an S. speciosa flower. Flowers can be nearly any color, and some species produce velvety flowers. Flowers can even be spotted or patterned. Some species, often cultivated by cactus and succulent enthusiasts, have very developed tubers.
Sinningias usually have periods of dormancy followed by periods of growth, but some cultivars have been designed to flower almost perpetually. It is also possible for a plant to fail to come out of dormancy. These plants should be grown in evenly moist soil with good drainage. An overly dry soil can prematurely induce a dormant period, while overly moist soil can cause the tuber to rot.
Regular light fertilization is best for most plants, though different cultivars have specific requirements. Many S. speciosa varieties require bright light and can be grown under fluorescent lights or in a greenhouse. Some cultivars grow well as outdoor plants, but many do not tolerate direct sunlight. Some plants are best grown in enclosures to ensure high humidity.