Motherwort (Leonurus cardiaca)

Lamiaceae or Mint Family
 

Tall weed with leaves in pairs and stems square in cross-section.  Leaves are toothed near the top of the plant, deeply cut into three lobes lower down, and cut into five lobes still lower.  Small, lilac, furry flowers in whorls just above each pair of leaves, except the lowest.  Blooms in the summer.

An introduced weed of waste places and gardens.  In Wildwood it blooms near the Outdoor classroom and along the Riverway.

A number of species in the Mint Family occur in Wildwood; all have irregular flowers in whorls, paired leaves, and square stems.  Height, leaf shapes, and arrangement of flowers above the leaves is distinctive of motherwort.