But the search does check everywhere. If you had searched only for the cultivar name, you'd get these results:
http://garden.org/plants/searc...
The results are from various parts of the database, including some of the sections you call specific.
Those custom databases aren't really separate from the main database. They're simply a convenience for people staying within those genera, and many of the custom databases have custom information fields that aren't present in the database as a whole (name of hybridizer, year of introduction, etc.).
