Quote:
Originally Posted by dionysus  right, i suppose that there are a lot of plants with orchid in their name but don't fall under orchidaceae. i think that orchids have to be epiphyteous(air plant essentially, or potential parasite) to be a true orchid. not sure though. |
The characteristic that makes an orchid an orchid is the configuration of their reproductive organs. Flowering plants (like a lily or tulip for example) have seperate pistils and stamens but in orchids, these two structures are fused into one structure called the
column. Orchids are the only flowering plants to bear this structure and this is what distinguishes an orchid form other flowering plants.
Some orchids are
epiphytes as you suspected, but being an epiphyte means that the plants grow in trees rather than in soil. Some but not all orchids are epiphytes. Others are
lithophytes (grow on rocks) and still others are
terrestrials (grow in dirt or other organic matter). Orchids are neither parasitic, as they do not feed off the tree on which they are growing, nor are they "air plants" as they do not rely on moisture and nutrients obtained from the air alone.
Happy Growing!