Orchidaceae A.L. de Jussieu. Orchid Family.

Contributed by Scott Ward & Alan Weakley

Key to Orchidaceae

A family of about 800 genera and 19,000 species, perennial (rarely annual), mycotrophic herbs (many epiphytic) and succulent-stemmed vines.

ID notes:Flowering plants are necessary for use of the key to genera. We attempt to be as specific as possible in our application of orchid morphology terms. Use of the term "flowers" refers to the entire flowering parts; however, we refer to specific portions of the flowers when necessary. Perianth segments refer collectively to the sepals and petals, which sometimes differ from one another. When crucial for identification, we also specifically refer to the dorsal sepals or lateral sepals. The lip refers to the labellum, which is a highly specialized median petal often modified for insect pollination, and is often a distinct feature used in orchid identification. Given the distinct nature (and function!) of the labellum, we also refer specifically to portions of this structure (e.g. middle lobe, lateral lobe) when applicable. Resupination in epiphytic orchids refers to the orientation of the flower in accordance with its main stem axis, thus while some flowers of epiphytic species may appear upright to the viewer (e.g. Epidendrum nocturnum), these flowers are technically resupinate given their opposing orientation to the main stems. Conversely, in some species (e.g. Prosthechea cochleata), the labellum is oriented upmost on the non-resupinate flower. For epiphytic orchids bearing pseudobulbs, inflorescences originate either basally (from the base of pseudobulb) or terminally (peduncles originate from the apex of pseudobulb). Pseudobulbs are non-root, vegetative structures often appearing as thickened basal structures on stems. Pseudobulbs are common on many species of orchid and their shape, level of compression, and size are often diagnostic, especially when plants are not flowering.

Ref: Brown (2003); Brown (2020); Correll (1937); Correll (1950); Homoya (1993); Luer (1972); Luer (1975); Pridgeon et al. (1999a); Pridgeon et al. (1999b); Pridgeon et al. (1999c); Romero-González et al. (2002) In Flora of North America Editorial Committee (2002a); Schuiteman & Chase (2015). Show full citations.

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