\Or`chi*da"ceous\, a. (Bot.)
Pertaining to, or resembling, a natural order
({Orchidace[ae]}) of endogenous plants of which the genus
Orchis is the type. They are mostly perennial herbs having
the stamens and pistils united in a single column, and
normally three petals and three sepals, all adherent to the
ovary. The flowers are curiously shaped, often resembling
insects, the odd or lower petal (called the lip) being unlike
the others, and sometimes of a strange and unexpected
appearance. About one hundred species occur in the United
States, but several thousand in the tropics.

Note: Over three hundred genera are recognized.