Understanding cultivars, genus and species!!! Help please!

Hi all....this little newbie is attempting to start her first journal, only to realize (sheesh, dare I admit this?)...that I don't really know the difference between 'cultivar', 'genus' and species! If I'm going to start this journal...I'd like to get it right. Would anyone care to give me a simple example? I don't know if I've chosen the right 'forum' to post this to...but hopefully someone out there will take pity on me! :-) Thanks!

Well, since I love trees, I'll use a tree as an example.

Using this name as an example: Ginkgo biloba 'Princeton Sentry'.

-Ginkgo is the genus name and is always capitalized.
-biloba is the species name and is always in all lower case letters
-'Princeton Sentry' is the cultivar name and is always in single quotes, never double quotes.

The above are always listed in that order: Genus, species, cultivar.
I hope this helps.
Mike

Here's a simple(ish) example.

Genus - Digitalis
Species - purpurea
Cultivar - Primrose Carousel

The genus name Digitalis indicates that it is part of a group of plants with similar characteristics. In this case it's the Foxglove group.

The species (specific epithet) purpurea indicates it belongs to a group of very alike individuals that when bred together reproduces alike offspring. In this case it's the common foxglove group that has (usually) purple flowers with wide, spotted mouths and felted leaves.

Cultivar is a shortened word from cultivated variety. Cultivars are plants that have been bred for a specific characteristic in this case (Primrose Carousel) they have been bred to produce yellow coloured flowers, rather than the purple.

Stimmins, the system of binomial nomenclature that we use to classify plants and animals was dreamed up by Carl Linnaeus in the 18th century. Look here for more details.
http://www.ucmp.berkeley.edu/history/linnaeus.html

YIPPEEEEE! Once again, Dave's Garden has come to the rescue!! This place is wonderful!! Treelover, Baa and raisedbedbob, many thanks for responding so quickly. I think I'm starting to understanding!! Of course,... you can all bet I'll be back with more questions! :-)
Sharron

Stimmins - Also there's a nice little feature called Garden Terms here on DG that is very helpful in times such as these......

Genus
http://davesgarden.com/terms/go/393.html

Species
http://davesgarden.com/terms/go/850.html

Cultivar
http://davesgarden.com/terms/go/229.html