A polyploid pink and white shower tree, Cassia javanica, produces diploid progeny

A purported tetraploid (2n=4x=56) plant of the pink and white shower tree, Cassia javanica, confirmed by guard cell measurement and root-tip chromosome count, was crossed to a diploid (2n=2x=28) plant of the same species to produce triploid (2n=3x=42) progeny that were expected to be sterile. The progeny, however, from six crosses were 2x. Flow cytometry was used to help determine that the purported 4x parent plant was in fact a mixoploid, consistent with a 4-2-4 periclinal cytochimera having 4x epidermal and cortex tissues with a 2x tissue layer between giving rise to haploid gametes.