The Collaborative International Dictionary of English v.0.48:

Lobelia \Lo*be"li*a\ (?; 106), n. [NL. So called from Lobel,
   botanist to King James I.] (Bot.)
   A genus of plants, including a great number of species.
   Lobelia inflata, or Indian tobacco, is an annual plant of
   North America, whose leaves contain a poisonous white viscid
   juice, of an acrid taste. It has often been used in medicine
   as an emetic, expectorant, etc. Lobelia cardinalis is the
   cardinal flower, remarkable for the deep and vivid red color
   of its flowers.
   [1913 Webster]

WordNet (r) 3.0 (2006):

lobelia
    n 1: any plant or flower of the genus Lobelia