The Collaborative International Dictionary of English v.0.48:

Marguerite \Mar"gue*rite\, n. [F., a pearl, a daisy. See
   Margarite.] (Bot.)
   The daisy (Bellis perennis). The name is often applied also
   to the ox-eye daisy and to the China aster. --Longfellow.
   [1913 Webster]

WordNet (r) 3.0 (2006):

marguerite
    n 1: tall leafy-stemmed Eurasian perennial with white flowers;
         widely naturalized; often placed in genus Chrysanthemum
         [syn: oxeye daisy, ox-eyed daisy, marguerite, moon
         daisy, white daisy, Leucanthemum vulgare,
         Chrysanthemum leucanthemum]
    2: perennial subshrub of the Canary Islands having usually pale
       yellow daisylike flowers; often included in genus
       Chrysanthemum [syn: marguerite, marguerite daisy, Paris
       daisy, Chrysanthemum frutescens, Argyranthemum
       frutescens]