How common are un-resupinated flowers? - Orchid Board

tropterrarium · #1 06-15-2011, 01:16 AM

I noticed on Epipactis gigantea in my yard some plants with one fully open, but upside-down flower. They have stayed that way for several days, so it is not a premature opening, and then the flower resupinates. Other flowers on the same stalk are normal, so it is not a plant-wide phenomenon.

I have not noticed this so blatantly on any other orchid. Are some species/groups more prone to such developmental anomalies? Any known causes?

Tindomul · #2 06-15-2011, 10:31 AM

I think its common in the Catasetum alliance, and in the Prostheca genus. Also in some very basal orchid genera (the orchids most closely related to non orchids).

RosieC · #3 06-15-2011, 12:33 PM

Can I ask a stupid question. Wondered about this several times.

What does resupinated mean?

Paul · #4 06-15-2011, 01:08 PM

A resupinate flower is one in which the flowerstalk does a 180-degree twist while it develops, bringing what would be the bottom of the flower to the top, and vice versa.
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This applies to the majority of orchid flowers, Rosie. When the buds first emerge, they tend to be oriented so the lip would be in the "up" position -- or at 12 o'clock if that is easier to visualize. (Though personally I think one needs to look at "up" as a relative thing here as the lip is generally facing the spike's central axis.) Then as the buds grow and mature, they twist -- reorienting themselves so that the lip is facing down .... the lip is now at the 6 on the clock. This is easily seen with most orchids like phals for example.

Nonresupinate flowers are those in which this twist doesn't occur, That results in the lip remaining in the upright (12 o'clock) position after the bud opens. The cockshell orchids (Prosthechea) are a good example.

tropterrarium · #5 06-15-2011, 03:55 PM

Possibly the best-known case or resupination is in orchids with a 180 degree twist. In some other genera/families (Dicot: Fumariaceae: Corydalis) there is a 90 degree rotation. When I took botany a few (maybe rather quite a few) years back, it was also called resupination. So not sure whether resupination implies 180 degree or just some kind of rotation with the orchid-180 being the best known. And I took botany in German, so there may cultural issue here between German and English.

Thanks Tindomul for the further comments.

RosieC · #6 06-16-2011, 06:07 AM

Cool thanks for the explanation.

In that case is Den unicum non-resupinated? It's lip is in the 12 o'clock position. However I guess if the bud starts the other way up then turns to bring the lip up it's still resupinated, is that correct? I'm not sure if unicum turns, just that it's lip is up.

My Den Stardust (a hyrbid of unicum) will produce most flowers resupinated (including the lip being down), but the odd flowers will stay with the lip facing up. This sort of says to me that unicum IS non-resupinated, but I'm not sure.