The strange world of orchids

Orchids may be famed for their elegant beauty, but some species have bizarre shapes, such as flowers that look like a monkey's face, or give off a foul stench to attract insects.

>>> World's rarest orchid discovered

The orchid family contains more than 20,000 species (four times the number of mammal species) in over 800 genera worldwide. Of these, about 2,000 species belong to the genus Bulbophyllum, found in tropical rainforests.

Orchids can live and grow in a wide range of climates, from humid tropical forests to frigid polar regions, high up in the canopy or even underground. To thrive, however, each species needs its own particular environmental conditions. Dendrobium alexandrae (pictured) grows best on moss-covered trees in cloud forests.

Orchid flowers may last only a few hours, or stay in bloom for as long as six months. Some plants, however, take several years to flower.

According to researchers, orchids produce a wide variety of distinctive scents, from foul and pungent to sweet, vanilla-like aromas. The rotting-meat smell of some species attracts flies, while pleasantly scented species lure bees to pollinate them.

Orchids can grow on or around rocks. Many species lead a simple life, sprouting from the ground like grass. Most orchids, however, are epiphytes: they anchor themselves to sturdier trees without parasitizing them, and mostly grow high above the ground.

The unusual arrangement of sepals and petals, forming a small trap, is the hallmark of the orchid Paphiopedilum spicerianum. Unlike the traps of carnivorous plants, this one does not digest insects; it simply lures them into falling inside so that they pick up pollen.

The specially structured inner petals and outer sepals give orchids a remarkable variety of unique shapes. Dracula orchids, also known as monkey-face orchids, get their name, meaning "little dragon" in Latin, from their long, thin, spike-like sepals.

The distinctive shapes of their petals and sepals help orchids attract the small animals that pollinate them. According to researchers, the long purple stripes of Warczewiczella amazonica (formerly Cochleanthes amazonica) help the flower attract insects.