Lynn, you're looking at Catalogue of Life information dated September 2012. Here's the COL information dated September 2013:
http://www.catalogueoflife.org...
Kevin, the rules of Latin names are simple. The nouns (the genera) are feminine, masculine, or neuter. The adjectives (most of the species) are also feminine, masculine, or neuter and they have to agree with the noun. That's why they change when the plant is moved to a genus of a different gender. Some species names are not adjectives, such as heuffelii, so they stay the same even after they've been moved to a genus with a name of another gender.
The perceivable differences between the two genera aren't a strong argument, Lynn. Think of Brassica rapa, for instance, which now includes broccoli raab, turnips, mustard greens, and bok choy. The genetic differences between those vegetables certainly seem obvious, but they all share the same genus and species name.
