Understanding the garden terms for my journal

I understand how to use the journal that's not the problem...the problm is I have no idea the difference between a cultivar or species or what the genus is of a plant. I've read the garden terms for each but I just want to make sure I'm understanding it correctly. So I thought I would give an example and someone can tell me how to enter it in my journal...because I know I entered my plants wrong...but I just wanted to be able to log what I had...until I took the time to learn.

Snail Flower - Vigna caracalla

Snail flower = common name
Vigna = Genus
caracalla = species

What about like hosta's? Would Hosta be the common name or the genus? Or is 'Patriot' the species?

Patriot = common name
hosta = genus

Any help would be greatly appreciated.

Thanks,
Lisa

Lisa, you've nailed it on Vigna caracalla.

In the case of Hostas and a few other plants, we commonly refer to them by their botanical name; hence....

Common name: Hosta (or Plantain Lily, if you happen to use that name)
Family: Liliaceae
Genus: Hosta
Species: (blank in most cases, as theyre mostly hybrids)
Cultivar: Patriot

Unfortunately, this situation is an exception to the rule in the US, where we tend to rely more on the non-Latinized common names for plants (you'll also sometimes see common names referred to as "vernacular" names.)

Thank you Terry! That really did help clear it up. Now for cleaning up my journal. :-)