Spanish Needles,  Bidens bipinnata
Asteraceae or Sunflower Family

Low plant, 1 to 3 feet tall.  Leaves opposite each other, finely divided into leaves that are further divided, lobed and toothed.  Stem square.  Flower head long and narrow, with a number of yellow disc flowers and generally no ray flowers.  Fruit a long slender needle-like capsule with 2-4 prongs on the end that catch on fur and clothing.

A weedy native.  Prefers dry, often rocky places and sometimes a weed in cultivated fields.  In Wildwood occasional in dry areas along Wildwood Drive and the bikeway.

The tiny, yellow, generally rayless heads are distinctive of the genus Bidens (although some Bidens do have rays).  Devil's beggar ticks (B. frondosa) is somewhat taller, and has leaves divided into 3 to 5 toothed leaflets. It often grows in wet places.