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On the significance of keiki in nature

February 10, 2013

A keiki is an asexually formed orchid plantlet, a copy of the mother plant. Keiki is Hawaiian and means ‘child’. In Dendrobium orchid keikis may form on older pseudobulbs, and are first seen as a cluster of orchid roots and a small pseudobulb.

In a garden situation this is a simple way of cloning a beloved orchid. Simply cut the keiki and tie it to another branch or tree. For instance, at Dokmai Garden we only bought two Dendrobium aphyllum but thanks to keiki formation we now have nine.

I originally thought this was a curious anomaly, because the pseudobulbs hang down and they would eventually fall down to the ground and die together with the keiki. This would happen in a garden situation, where orchids either hang in pots, or are grown in trees with a generous distance to the next tree, to allow a scenic view of both tree and orchids.

However, in nature trees grow much more densely, and understorey shrubs and saplings would rub against trees. As can be seen from the picture below, a pseudobulb rubbing against another branch, allows the orchid individual to take a leap of 30 cm. Cloning within a tree would provide massive blossom which would give stronger signals to pollinators, and the shortened distance between flowers would increase the probability of successful pollination before the insect gets caught by cobwebs and predators when flying between trees. Increased fruit formation would result in greater abundance of seed production, and since most seeds fall near the mother plant, the clone would be mixed up with genetically different daughter seedlings and subsequent crossings would contain even higher genetic diversity. This is a time-consuming process, but epiphytic orchids can probably become as old as the branches or stems on which they grow. In the case of teak, a main stem may become 1500 years. Virgin forests are extremely rare in Southeast Asia, almost everything has been logged, and the orchid abundance in the secondary forests is just a fragment of what early explorers described.

By slowly creeping around in trees some orchid individuals may still survive when the light intensity changes. A sun-loving orchid may succumb due to shade from another tree, but by changing positions it may have a few more years of reproduction.

It is also possible that keikis falling down from tall trees may get entangled and established in crowns of lower trees, especially on steep mountainsides which is a characteristic of the Chiang Mai hills and mountains.

keiki 1.72This Dendrobium secundum (Orchidaceae) has a few fresh pseudobulbs, but a wrinkled old pseudobulb which grew out to the right has formed a keiki which has attached itself on the branch. This happened within one rainy season (a few months).

keiki 2.72A close-up photograph of the keiki. The tree is the deciduous snapdragon tree, Gmelina arborea (Lamiaceae) which grows in the Dokmai Garden parking.

Text & Photo: Eric Danell

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2 Comments leave one →
  1. marcel.prahin@geneva.msf.org permalink
    February 11, 2013 5:58 PM

    Hello Khun Eric or khun Ketsanee,

    Would it be possible to change the e-mail reception from this one marcel.prahin@geneva.msf.org to thaimac@infomaniak.ch

    Thank you in advance and good day Mac MSF- CH Nord Soudan, Sud Soudan, Lebanon, Iraq, Honduras, Guatemala, Mexico Tl. 0041 (0)22 849 84 24 / 0041 (0)22 849 84 84 Fax 0041 (0)22 849 84 88

    • February 11, 2013 7:53 PM

      Dear Marcel,

      You need to make the change yourself. Click ‘Manage subsriptions’ at the bottom of the automatic e-mail. First you unsubscribe, and then you go to the website and subscribe again, using your new e-mail.

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