orchid

Orchid refers to any member of the orchid family, Orchidaceae, a diverse and widespread group of flowering plants. The family includes tens of thousands of species and many hybrids, making it one of the largest plant families. Orchids are known for their complex flower structures, with bilateral symmetry, a highly modified petal called the labellum (lip), and a reproductive column that fuses the stamens and pistil. Flowers often exhibit intricate pollination strategies, including specialized shapes, fragrances, and the attachment of pollinia to pollinators such as bees, moths, and butterflies. Many orchids have velamen-coated roots and, in some forms, pseudobulbs for water storage.

Orchids are found worldwide but are most diverse in tropical regions of Asia, the Americas, and Africa. They occupy a range of habitats, from tropical rain forests to grasslands and high mountains. A large proportion are epiphytic, growing on tree trunks or branches rather than in soil, while others are lithophytic or terrestrial.

Humans cultivate orchids as ornamental plants. Genera such as Phalaenopsis, Cattleya, Dendrobium, Oncidium, and Vanda are popular in horticulture. Cultivation typically requires well-draining media, moderate to high humidity, bright but filtered light, and careful watering. Propagation is commonly by division or, for many species and hybrids, by tissue culture.

Conservation concerns include habitat loss and over-collection in the wild, with trade regulated under CITES for many species. Orchidaceae also serves as a model group for studying coevolution, pollination biology, and symbiotic relationships with mycorrhizal fungi critical for seed germination.