Your dogwood is a shrub and has the small clusters of flowers. There are several varieties of shrub dogwood that can be hard to tell apart if you aren't a botanist. There is one tree (Pagoda dogwood, Cornus alternifolia) that has similar flowers to the shrubs.

There are two common types of dogwood tree in the eastern half of the country which have the "four leaf clover type" of blossoms which are actually 4 large bracts (the "petals") and then in the center a small cluster of blossoms which if fertilized will turn fruit. Cornus florida is the native flowering dogwood and has its flowers before the leaves come out. Cornus kousa, is an Asian dogwood and is commonly called Kousa dogwood. It has leaves when it flowers a few weeks later than the native flowering dogwood. The fruit looks different on these two, and if you search for images you can easily see the difference. Either of these trees can have white or pink flowers, depending on the particular plant selection you are growing.

all because of the use of common names ...

if you want to learn.. you need to find the latin names.. and then learn the characteristics of each type ...

sometimes.. when relying on common names.. you find out.. they arent ever related at all ... like the butterfly bush.. which is used for buddelia and whatever the latin is for butterfly weed

ken

Ken-"Butterfly weed" is the common name for Asclepias tuberosa. You would never be able to confuse it for a butterfly bush. Unless you were really, er, confused...