Sunday, August 14, 2011

Triphora trianthophora, Three Birds Orchid

The exceedingly rare and elusive Three Birds Orchid flowered profusely in northern Indiana this year, in high quality forested sites.
It's an unusual plant for many reasons, but its strangest characteristic is the timing of anthesis. Most plants have three flower buds, and all plants in a forest will open their first flower on the same day, as if they could communicate. Twins like the ones shown here are only occasional.

The flowers only last a day, and about two or three days later, the second set of buds will open, an so on. If your timing is not perfect, you are not likely to see the plant in flower.

It sometimes lies dormant for several years, then suddenly flowers show up in mass profusion. After initially seeing this plant in 1996, open flowers eluded me until now. I owe a special debt of gratitude to Pete Grube for keeping me posted on the status of the plants, or I probably would have forgotten about this species entirely.


Prem Subrahmanyam said...

According to members of the North American Native Orchid Conference, it is a somewhat cooler-than-usual night that initiates flowering...since all plants in a colony experience roughly the same temperature differentials, they are able to coordinate themselves using this event.

A similar mechanism happens with Dendrobium crumenatum in the afternoon temperature differential of ten degrees or more (usually caused by a well-timed afternoon shower) will initiate buds, which open ten days later and last one day. Again, entire colonies can synchronize using this temperature differential, all blooming simultaneously on that day.

The Florida Native Orchid Blog

Keith said...

In Orchids of Indiana, Mike Homoya describes this phenomenon quite well, and refers to it as "thermoperiodicity." Thanks Prem, for sharing your insights!