question about bifoliate Catts.

[exasperatus2002]

Ok this is a spin off (didnt want to hijack anothers thread) of the Cattleya question post regarding sheaths. I have several unifoliates and a bifoliate Cattleya's. My unifoliates have only had a sheath when preparing to flower (Blc. Chia Lin 'New City" AM/AOS). My others are not blooming size. My Bifoliate is Guaranthe aurantiaca. It always has a sheath on all of its PB's except for the newest PB's. But it will only flower once a year from the next oldest PB. The sheaths are always green and dont dry up until after flowering.

Is this typical behavior of bifoliates?

[kmarch]

Originally Posted by exasperatus2002

...My unifoliates have only had a sheath when preparing to flower...My bifoliate is Guaranthe aurantiaca. It always has a sheath on all of its PB's except for the newest PB's. But it will only flower once a year from the next oldest PB. The sheaths are always green and dont dry up until after flowering.

Is this typical behavior of bifoliates?

For those catts that do have sheaths, they don't grow sheaths later, they have them from start. The buds inside may not develop until later, but the sheath will be there from the start. Catt species are more predictable than hybrids regarding plant habit, more specifically sheath habit, and they will perform pretty consistently. The fact that your Guar. aurantiaca doesn't flower off new growths but flowers off the previous years' growth may be due to your environment/conditions, as I have seen them flower off the newest growth.

For hybrids there is not general typical beharior that can be applied to all. They are such a mix of uni- and bifoliates that it's a craps shoot what kind of sheath habit you'll come up with.

[JLu]

Catts (let's stick to species for simplicity), follow two different growth and bloom patterns. First there is the growth-root-bloom and second the growth-bloom-root.

So a new growth starts: In pattern one, the growth begins (spring) and matures (late spring/summer), roots grow, and then a sheath appears (fall). Usually this sheath will dry and after a rest period (winter), the bud will appear in the dry sheath and bloom in spring.

In pattern two: The growth appears and matures (spring). When the growth matures it produces a sheath and blooms (summer/fall) and then roots grow. So these bloom from green sheaths. They rest in winter.

Since there is a species, unifoliate Catt blooming every single month of the year, these timings must be shifted around slightly.

Bifoliate Catts act similarly. Occasionally, any Catt can bloom without a sheath. It seems to me to occur more often with bifoliates.

There are four Catts that make up the rules as they go: aclandiae, violacea, walkeriana, and nobilior. Their behaviors are more complex.

In your case with aurantiaca, it grows-roots-blooms. So it puts out a fall sheath that dries, rests in winter, and blooms from that sheath in February/March. Thus your observation that it blooms from the second oldest growth. That's not precisely correct, but I can see how you arrived at that conclusion.

As kmarch said, it is impossible to predict the behavior of a hybrid, but after you figure it out, it should be consistent. While this Catt behavior is explained in almost any Catt literature, the best explanation is in Orchid Digest, Oct,Nov,Dec 2004, Vol 68 No.4. This is for sale from Orchid Digest Corp. Since you are so interested in these Catts, I urge you to get some good Catt reference material.