Orchidaceae

Abstract

Perennial terrestrial or predominantly epiphytic herbs, rarely shrubs or lianas, very rarely saprophytic and without chlorophyll or completely subterranean; R often tuberous in terrestrial taxa, with multi-layered velamen in epiphytic taxa; stems virtually absent, or forming corms or rhizomes, often distinctly swollen to form pseudobulbs, often rooting at the nodes; L entire, spirally arranged (sometimes distichous, rarely opposite or whorled), sometimes Sc-like or absent, often fleshy; Inf racemes or panicles, or Fl solitary; Fl mostly bisexual (rarely unisexual and plants dioecious), 3-merous, often resupinate; Per of 3 + 3 usually petaloid Tep, one of the inner Tep (labellum) usually much larger and / or differently coloured; St 1 (-3), mostly united with the Sty to form a Gy; pollen normally united into complex pollinia (rarely pollen dustlike); Ov of 3 united Ca, inferior, normally I-locular; Fr capsules opening with 3 (or 6) longitudinaly slits but remaining closed at either end; Se numerous, dustlike with undeveloped minute embryo.