The Collaborative International Dictionary of English v.0.48:
Orchis \Or"chis\, prop. n.; pl. Orchises. [L., fr. Gr. ? a
testicle, the orchis; -- so called from its tubers.]
1. (Bot.) A genus of endogenous plants growing in the North
Temperate zone, and consisting of about eighty species.
They are perennial herbs growing from a tuber (beside
which is usually found the last year's tuber also), and
are valued for their showy flowers. See Orchidaceous.
2. (Bot.) Any plant of the same family with the orchis; an
Note: The common names, such as bee orchis, fly orchis,
butterfly orchis, etc., allude to the peculiar form
of the flower.