Kingdom Plantae  Plants
- Subkingdom Tracheobionta  Vascular plants
-- Superdivision Spermatophyta  Seed plants
--- Division Magnoliophyta  Flowering plants
---- Class Magnoliopsida  Dicotyledons
----- Subclass Dilleniidae Â
------ Order Violales Â
------- Family Cucurbitaceae  Cucumber family
-------- Genus Cucumis L. -- melon P
--------- Species Cucumis sativus L. -- garden cucumber P

You can find more on the link below. Basically, you can find any type of vegetable this way. The easiest is to search for the GENUS or SPECIES of the vegetable you are trying to find (e.g. try "carrots genus and species" in google for example) and then look for these in the data base (in the example, you would look up Genus: Dacus Species: carota in the database. "Dacus" (genus) and "Carota" (species) was information returned by google).

Here is a link that might be useful: USDA Plant classifications

Sorry this is a better link:

Here is a link that might be useful: USDA plant classification