Family: Orchidaceae
Common name: orchid family [Zomlefer, pp. 293-297]
Diversity: Worldwide: 750 genera; 20,000 species
U.S.: 21 genera
PNW (Hitchcock & Cronquist): 14 genera
Flower -- Vegetative Features -- Economic Importance -- Flower Images-- Web Sites

Sexuality: bisexual, rarely unisexual
Symmetry: zygomorphic
Inflorescence: raceme, spikes, or panicles
Calyx (sepals): 3, green and sepaloid or colored and petaloid
Corolla (petals): 3, dissimilar, lower petal often as a lip (=labellum) that is variously modified, sometimes including a spur
Androecium: 1 or 2, pollen usually aggregated into several (2-8) masses (=pollinia), pollinia may have sticky portion for attachment to pollinator
Gynoecium: 3 united carpels, inferior ovary (=epigynous), parietal placentation, 3 stigmas, often two fertile, the third modified into a sterile outgrowth (=rostellum)
Fruit: capsule
Other features: stigma, style, and androecium united into a complex structure called the column (=gynandrium), with anthers above and styles below, separated by rostellum modifications of column are responsible for much of pollinator diversity

Vegetative Features
pseudobulb in many tropical and subtropical species, (water storage organ in modified stem)
Leaves: alternate, simple, entire, often in two ranks, succulent, sheathing at the base
Life-history: perennial
Habit: herbs, including terrestrial (50%), epiphytic, and saprophytic (lacking chlorophyll). Obligate mycorrhizal associations.
Distribution & Ecology: cosmopolitan, especially diverse in the tropics
Some Northwest Genera: Calypso, deer's-head orchid
Corallorhiza, coral root
Cypripedium, lady's slipper
Epipactis, helleborine
Platanthera (=Habenaria), bog/rein orchid
Listera, twayblade
Spiranthes, ladies' tresses

Economic Importance
Crops: Vanilla, vanilla beans
Ornamentals: very important floriculture industry
hybrids form readily between species and even genera (reports for some hybrid cultivars trace their origin to 20 species in 5 genera)
Weedy and pest species:

Examples Orchidaceae Calypso
Orchidaceae Corallorhiza
Orchidaceae Cypripedium
Orchidaceae Platanthera
click on the genus name for a flower image

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