Orchid Aerial Root
This complex botanical ranges in size from tiny to gigantic, with species growing as tall as 25 feet (viz. Grammatophyllum speciosum). Even with such diversity, the flower on every orchid expresses bilateral symmetry, containing three petals and three petal-like, outlying sepals. Generally, there is a distinct, bottommost petal called the labellum that is larger and manifests a novel shape and color. This 'lip' contains specialized cells that secrete nectar to attract insects during reproductive pollination. Botanists theorize that many of the physical characteristics peculiar to specific orchid species have selectively evolved to attract specific pollinating insects or animals, and even include structures that so resemble female insects that the male insects try to mate with them. At the center of the flower is a structure formed by the fusion of stamens and pistil called the column.