This is a fairly perfect specimen of star magnolia, Magnolia stellata, growing in the East Village.
Star magnolia blooms, in general, about 2 weeks or so earlier than saucer magnolia. They are both fabulous spring plants.
Star magnolia, is in that weird category of small tree/large shrub. Too small for a tree, too big for a shrub. I try to sidestep these definitions as often as possible because there is no clear cut answer, though I lean to categorize this as a tree.
Magnolia is one of the oldest genera of flowering plants, indeed Magnoliaphyta is the phylum that includes most angiosperms.
Stellata, as one can guess, means star-like and refers to the somewhat starry, strappy tepals of this flower. Tepals, like bracts, are another evolved versions of plant strucutures that, while not connected to the sexual properties of a flower, are key in attracting the right pollinators and ensuring the plant survives and reproduces.