I'm with you Diane56Victor I have 3 polyploid seedlings of C. amethystoglossa. They are all doing great but it will definitely be another 3 years before they bloom. Even then they will only be half size I bet. They get huge! I love those giant Cattleyas! Can't wait for mine to be 3' tall!
Stephen can answer better, but it depends on ploidy. 4n plants can be in continuous growth if you have warm conditions, while 2n plants tend to grow once a year. In any event, longer than for most other Cattleya species and longer than almost every hybrid.
2n and 4n are shorthand for sets of chromosomes. 2n is the amount that most natural species have (one pair). Plants can have multiple sets of chromosomes (this would usually be fatal to animals) 4n is a plant with double sets of chromosomes.
In orchids this makes the plants have thicker larger leaves and flowers. They also usually grow a little slower but most people are ok with that for the sake of the robust flowers
I actually made a video a year or two ago comparing 2n vs. 4n blooming amethystoglossas. Both of these plants are blooming for me right now and I'll post pics soon: https://youtu.be/28yc40Btsyc
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My memory tells me the sound isn't great on that video. I was still trying to figure out how to get decent sound in my videos at that time!
I got a 4n seedling from SVO 2 years ago and I don't think its going to bloom for another 2 years based on size. I bought it with a 4n Dowiana (likely to bloom this summer), and encyclia phoenecia (bloomed 6 months ago), and a aurantiaca f. punctata (bloomed a year ago).
The 4n amethystoglossa is a super healthy plant though, attractive even without flowers.