A group of orchids, often known by such descriptive names as fly orchid, bee orchid, and spider orchid, carries the deception further, actually mimicking the insects themselves.
The flower (Rossioglossum ampliatum, above right) is a member of the Oncidiinae group of orchids in the tropical Americas.
There is an urgent need to search for better morphological synapomorphies of the major clades identified here, and to determine just how much homoplasy is present in morphological characters that were previously regarded as essential to circumscribing genera and species within this important group of orchids.
The most dense group of orchid flowers of last June was now almost gone.
Thus, the evolution of a completely saprophytic life cycle in different groups of orchids is not surprising.
Three major groups of orchids have become predominantly fly-pollinated: the subtribe Pleurothallidinae in tropical America, containing more than 4,000 species; the Bulbophyllum group of about 1,800 species found mainly in the Old World; and the large genus Pterostylis and its relatives in Australia.
By using new gene sequencing methods, a team led by Thomas Givnish, a plant ecologist at the University of Wisconsin, Madison, created a phylogeny of orchids with an unprecedented 75 chloroplast genes from 39 species, representing almost all major groups of orchids, as well as from 96 distant relatives among all flowering plants.
The ancient origin, conservation and unique expression (see below) of these distinct groups of orchid-specific genes suggest that they have key roles in determining the organ identities behind the characteristic orchid floral morphology [ 42, 62].
As soon as you enter the tropical section of the Princess of Wales Conservatory, the glasshouse around which the festival is centered, you are confronted with an astonishing sight: a group of vanda orchids, big blowsy blossoms in purple, white, orange, yellow and blue, which appear to be floating in mid-air (they're actually suspended from the roof with virtually invisible nylon line).
Tolumnia genus (equitant Oncidium) is a group of small orchids with vivid flower color.
No study to date has subjected members of Orchidaceae to such kind of macroevolutionary analysis, and there are several reasons detailed below why this group of tropical orchids provides a particular interesting system for the study of selfing evolution.
