Indian tobacco (Lobelia inflata) is an annual native plant in North America (eastern and central regions).  It blooms starting in mid-summer and continues blooming until the first hard frost in the fall.  Flowers are quite small so it takes a close look to see their wonderful design.

Leaves have distinct margins.  They are finely toothed with a bit of waviness.  They also have white dots scattered along the margin.

Fertilized flowers develop into inflated seed capsules (hence the species name of inflata).  This next photo shows the alternate leaf arrangement along with a few seed capsules.

Here's a close view of a ripening seed capsule.
Some Indian tobacco plants consist of a single upright stalk.  Other plants develop side branches, which also grow flowers and capsules, from the central stalk.

Watch this video about Indian tobacco (Lobelia inflata) to see close-up views of the small flowers, the white dots on the leaves, and the tiny brown seeds.

(Here's the same video as posted on YouTube.)