Asters are in bloom now in gardens and along roadsides throughout the South.  They are rather non-descript when they are not in bloom and then suddenly they explode!  They are a beautiful and essential part of the fall landscape to me.  Previously known as Aster, these are now in the genus Symphyotrichum .  It's a mouthful.  I saw recently where someone affectionately referred to them simply as "ex-Aster".  Much easier to say!  Here are some the ones blooming in my yard now:

Calico aster (Symphyotrichum lateriflorum) is a rather petite plant and usually found on the edges of woodlands.  It gets it's name from the multi-colored look of the blooms.  The difference in the color is attributed to the maturity of the inner disk flowers.  Before they open they are pale yellow, but they look purple once they open.

Georgia aster (Symphyotrichum georgianum) is perhaps my favorite aster.  The blooms are the largest of any that I know - the flowers can be up to 2 inches wide.  Their deep purple color is complimented by the dark purple center.  Similar to the Calico aster, the disk flowers are pale yellow when in bud and purple once they are open.  This plant is rather uncommon, and habitat destruction is decreasing it's natural range.

Aster patens (Symphyotrichum patens) is also a purple aster.  I have the two asters blooming right next to each other and sometimes they mingle.  The bloom is smaller, and it has the more common yellow center.  The leaves are very similar between the two: auriculate (eared) and clasping at the stem.  Georgia aster used to be considered a variety of Aster patens: Aster patens var. georgianus.

Bushy aster (Symphyotrichum dumosum) is aptly named! At my house there is one near the front porch and it bursts into a blooming bush this time of year.  Another common name for it is "rice button aster" because sometimes the blooms are quite small.  Here it is mixing with a late cardinal flower (Lobelia cardinalis):

Aster concolor (Symphyotrichum concolor) is what I call this one although it apparently is also known as Eastern silver aster.  Sometimes it is easier to hold onto the old names!  This one has an unusual bloom arrangement - the blooms are clustered tightly around the stem.

This last aster may be the same as Bushy aster but it never gets quite the same shape.  The flowers are arranged neatly along the stem and the whole effect is rather angular, not as "bushy" as the other one.  I think it is a form of Symphyotrichum ericoides.  If you don't have any asters, I'd encourage you to get some.  New England aster (Symphyotrichum novae-angliae)  is usually available in stores this time of year and is certainly one of the more floriferous ones.