What makes an orchid, an orchid?

There are several features that distinguish

orchids from other plant families, all which correspond to the structure

of the flower. In all orchids, the male and female parts (stamens and

pistil) are fused into a single structure called a Column, this is

probably the most important distinction. Also, orchid flowers all have

bilateral symmetry (the flower is symmetrical when you divide it

vertically down the middle), and are comprised of three sepals and three

petals, with one petal being quite different from the others which is

referred to as the lip. All orchids also have microscopic seeds,

resembling spores, which require a symbiotic relationship with a

particular fungus species in order to germinate. This why orchids grown

from seed by humans must be grown "in vitro" in a laboratory.