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; although some genera have distinguishing vegetative features. “Flowers" refers to the entire flowering parts (perianth to pollinia); perianth segments refer collectively to the sepals and petals, which sometimes differ from one another. Dorsal vs. lateral sepals can sometimes differ, and mention is made of this. The lip refers to the labellum, a highly specialized median petal often modified for pollination, and is often the most distinct feature at the genus level. Given the distinct nature (and function!) of the labellum, nuanced references to the median or lateral lobes are sometimes made. Resupination in orchids refers to the orientation of the flower in accordance with its main stem axis. Lip below typically refers to resupinate flowers, the lip lowest on the flower. Lip above is readily apparent in some taxa (e.g., Platanthera nivea, Calopogon spp., Prosthechea cochleata). For epiphytic orchids bearing pseudobulbs, inflorescences originate either basally (from the base of pseudobulb) or terminally (peduncles arising from apex of pseudobulb). Pseudobulbs are non-root, vegetative structures appearing as thickened masses throughout stems at many internodes (homoblastic) or at a single (usually more proximal) internode, or heteroblastic. Pseudobulbs are common on most epiphytic species of orchid and their shape, level of compression, and size are often diagnostic.

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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