4. Morphology of orchids

This chapter contains a detailed overview of the varied and complex structure of orchids. The morphology of terrestrial orchids is explained and compared with that of epiphytic orchids. Annotated composite photographic images of floral and vegetative orchid structures, and scanning electron micrographs of seeds are included. Although molecular methods are increasingly being used to elucidate the evolutionary relationships among orchids, most systems of classification are still based mainly on morphological characters. Specialised terminology is required in order to formulate precise unambiguous descriptions of these plants. Although overt use of technical terms was avoided in this section, some specialised terminology is inevitable and a glossary of terms is provided to assist the reader.