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Thursday, December 6, 2012

Mormodes sinuata, The Goblin

Mormodes sinuata. The yellow column is twisted to the side, exposing the anther.
Mormodes sinuata ABG # 07-2342 flowering at the Fuqua Orchid Center
'Like a goblin'--is the fanciful etymology of Mormodes Lindley (from the Greek mormo, meaning 'goblin'; and odes, meaning 'like a') describing this orchid's strange male flower with its twisted column. I can imagine how the features of a goblin's face might twist as it breaks into a grin.

Why would an orchid flower have a twisted column? Because it's part of a unique pollination mechanism. The twisted column places the pollinarium (the pollinia, stipe and sticky viscidium) in the correct position on the pollinator's thorax.

Charles Darwin was the first person to investigate how Mormodes flowers are pollinated when he studied Mormodes ignea (published in The Various Contrivances by Which British Orchids and Foreign Orchids are Fertilized, 1862).

The flower's fragrance attracts a male Euglossine bee (genus Euglossa). As the bee lands on the lip, it strikes the apex of the column, opening the anther cap. The pollinarium, with its sticky disc, swings forward onto the back of the bee. After 30 minutes the pollinia packet dries and uncoils into the correct position for placement onto the female flower.

Reading Contrivances again I have to admire Darwin's patient and painstaking attention to minute detail as he analyzes this whole procedure. "At the close of the twelfth trial I was in despair...," he laments. But he persists. With only twelve flowers at his disposal, Darwin figures out the mechanism using needles of different diameter in place of a pollinator.

Several more species of Mormodes have flowered this week. More pics will follow!


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