Source : Webster's Revised Unabridged Dictionary (1913)

Sharewort \Share"wort`\, n. (Bot.)
   A composite plant ({Aster Tripolium}) growing along the
   seacoast of Europe.

Source : WordNet®

Aster tripolium
     n : a common European salt-marsh aster [syn: {sea aster}, {sea
         starwort}]