Bulbs are the most common form of them. Orchid bulbs are not segmented like onions or lily bulbs, they are a homogenous mass of starch which develops roots, a stem with leaves and one or more daughter bulbs. Blooming orchids have usually two bulbs, an old from the last year and a new one. Later the old bulb dies and the new begins the rest.
Two big subgroups of bulbs can be formed: The Dactylorhiza group with forked, hand-like bulbs and the Orchis group with round bulbs. Formerly, both groups have been treated as one. Some orchids like Platanthera or Spiranthes have carrot-shaped bulbs.
