This section is from the book "Who's Who Among The Wild Flowers", by W. I. Beecroft. Also available from Amazon: A Field Guide to Edible Wild Plants.
Blue Curls: Heart-of-the-Earth: Brunella.
Prunella vulgaris. Mint Family. June - Sept.
Found in fields, waste places, along roadsides, throughout the United States. Naturalized from Europe.
Tiny, purple, varying to white, lower lip slightly fringed, borne in a dense head, terminating stem 6 - 12 inches high.
Opposite, oblong, narrowed toward the tip, slightly toothed.

Self-heal.
 
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