Introduction

The Gesneriaceae are a mid-sized to large plant family comprisingapproximately 2500-3500 species in 120-135 genera, distributedprimarily in the tropics with a few temperate species in Europe, China and Japan. The majority of species are herbaceous perennials, but they also can be annuals, shrubs, lianas, and trees. Many species (20%) are epiphytic, and the Gesneriaceae ranks among the top ten plant families in terms of absolute numbers of epiphytic taxa.

The Gesneriaceae are often referred to as tropical Scrophulariaceae and are closely related to this plant family. They are also closely related to Bignoniaceae and Acanthaceae but are distinguished from these families by the combination of five-lobed corollas, parietal placentation, and presence of endosperm in most species.

Figure 1. Cyrtandra hawaiiensis X Cyrtandra calpidicarpa from Hawai'i. The Hawaiian species of Cyrtandra represent an intriguing evolutionary story in that all 54 species are found only on the Hawaiian islands and have resulted in 75 interspecific, naturally occurring hybrids.

The Gesneriaceae are primarily a tropical family found in both New andOld World tropics, although there are some temperate representatives inEurope and Asia. For the most part, the subfamily Gesnerioideae is foundin the New World, the exceptions being members of the tribeCoronanthereae which are also found in Australia and the South Pacific. Cyrtandroideae are restricted to the Old World. Members of the tribe Klugieae, which has traditionally been placed within the subfamily Cyrtandroideae, are also found exclusively in the Old world, the one exception being Rhynchoglossum azureum from Central America.

Figure 2. Cyrtandra oxybapha from Hawai'i, a representative of theCyrtandroideae.