UC Irvine

SUMMARY: Sugars present in the floral and extrafloral exudates from a number of orchid species have been analysed. All contain fructose, glucose and sucrose. Raffinose is the next most common sugar and stachyose occurs less frequently. Cellobiose, gentiobiose, lactose, maltose, melibiose, melezitose and a few large oligosaccharides may also be present. The distribution of these sugars in orchids may have some chemotaxonomic implications. There appears to be no correlation between the sugar content of exudates and orchid pollinators. This would seem to suggest that scent, form and colour are the major attractants to pollinators in orchids. Floral and extrafloral exudates in orchids may also function as attractants for ants which probably feed on them and repel grazers.