Thanks for the great links, everyone! Now I know that the cultivar name should NOT be italicized:
Genusname speciesname 'Cultivarname'
Now I'm sure that I've been making grade school mistakes when I capitalize Petunia and Zinnia. But I
like capitalizing their names! They seem like proper names. But I guess not.
It sounds like Dave's suggestion would be a great application for the Mass Databox Proposal tool.
P.S. Dave's HTML codes are here:
http://garden.org/special/page...
and if you remove the spaces:
[ i]This is italic[ /i]