Learn About Orchids and Orchid Care

Learn About Orchids and Orchid Care

Tuesday, March 15, 2005

Reproduction

It is in the variety and the very refinement of their reproductive methods that orchids truly amaze. Each time, the lip serves as landing pad for the insects. This labellum has the right color and the right form to attract the right insect. After pollination, the epigynous ovary start developing and produces a many-seeded capsule.

  • The Paphiopedilums (Lady Slippers) have a deep pocket that traps visitors, with just one exit. Passage through this exit leads to pollinia being deposited on the insect.
  • A Eurasian genus Ophrys has flowers that look and smell so much like female bumble bees that males flying nearby are irresistibly drawn in, such as with the Bumblebee Orchid (Ophrys bombyliflora). The viscidium, and thus pollinia, stick to the head or the abdomen of the bumblebee. On visiting another orchid of the same species, the bumblebee pollinates the sticky stigma with the pollinia. The filaments of the pollinia have, during transport, taken such position that the waxy pollen are able to stick in the second orchid to the stigma, just below the rostellum. Such is the refinement of the reproduction. If the filaments hadn’t taken the new position, the pollinia could not have pollinated the original orchid.
  • An underground orchid in Australia, Rhizanthella slateri, never sees the light of day, but manages to "dupe" ants into pollinating it.
  • Many Bulbophyllum species stink like rotting carcasses, and the flies they attract assist their reproduction.
  • Catasetum saccatum, a species discussed briefly by Darwin actually launches its viscid pollen sacs with explosive force, when an insect touches a seta. He was ridiculed for this by the naturalist Thomas Huxley.
  • Some Phalaenopsis species in Malaysia are known to use subtle weather cues to coordinate mass flowering.
  • Some Phalaenopsis, Dendrobiums and Vandaceous species produce keiki, offshoots or plantlets formed from one of the nodes along the stem, through the accumulation of growth hormones at that point.
The filaments of the pollinia of some orchids dry up, if they haven’t been visited by an insect. The waxy pollen then fall on the stigma. This way, the orchid self-fertilizes.

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