Gesneriad Plant Characteristics

The following is taken from the Flower Show Manual For Judges And Exhibitors prepared by the American Gloxinia & Gesneriad Society.

Plant size ranges widely from the tiny Sinningia pusilla to tree forms like Negria and Solenophora.

The root type of all gesneriads is fibrous, but, in addition, two storage structures and propagation mechanisms may occur. Tubers are stem bases that are swollen, continue to enlarge as plants grow, and are perennial structures. Scaly rhizomes are stems that are compressed, resemble pinecones, and form after each growing season.

A number of gesneriads form flat rosettes of leaves. Those with stems may be erect, spreading or trailing. Leaves may be quite small to large, opposite or whorled, rarely alternate. The leaf pairs may be equal in size or strongly unequal. Leaves have entire margins or are scalloped or toothed. Their texture with a covering of silky or woolly hairs. Some leaves are marked with contrasting veins or patches of red or white on the top or reverse surface.

Flowers come in a variety of shapes from flat or saucer-shaped, bell-shaped to narrow tubular or inflated. The calyx can be colored, elaborately fringed, or persistent. Both corolla and calyx have five lobes. Gersneriad flowers are complete, containing two to four stamens and a pistil with stigma bilobed or mouth-shaped. Fruit may be a berry, a dry capsule, or a fleshy capsule. Most seeds are dust like, large ones close in size to a caraway seed. On rhizomatous plants, propagules may occur in leaf axils in place of flower formation. Propagules look like rhizomes but form above ground.

One very useful characteristic of gesneriads is ease of propagation. Stem cuttings, stolons, leaves, sections of leaves, propagules, scaly rhizomes (whole or even a single scale), tubers, and seeds will produce new plantlets. Despite the very small size of seed, sturdy seedlings develop.

Most gesneriads will perform well in normal household temperatures. A few need cooler temperatures to set buds. Many epiphytic gesneriads, which prefer to grow on tree branches or moss-covered rocks, develop a shallow root system well adapted to pot culture.