Autumn comes in many colors, but yellows tend to predominate in most plants that use September as their blooming anniversary. Most of the yellows are in the sunflower family, too, with an eccentric thistle, ragweed and daisy choosing other colors.

Goldenrods number more than a half dozen species here, covering field after field, marsh after marsh and prairie as well as forest edges.

It is not surprising that one goldenrod's common name is old-field goldenrod.

These many blooms follow a scheme followed by the bigger sunflowers, with the individual flowers so small they are nearly unrecognize...