The Collaborative International Dictionary of English v.0.48:

Quamash \Quam"ash\, n. (Bot.)
   See Camass.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Camass \Cam"ass\, n. [American Indian name.] (Bot.)
   any of several plants of the genus Camassia of North and
   South America, especially the blue-flowered liliaceous plant
   (Camassia esculenta) of northwestern America, the bulbs of
   which were collected for food by the Indians. [Written also
   camas, cammas, and quamash.]

   Syn: camass, quamash, camosh, camash.
        [1913 Webster]

   Note: The Eastern cammass is Camassia Fraseri.
         [1913 Webster]

WordNet (r) 3.0 (2006):

quamash
    n 1: any of several plants of the genus Camassia; North and
         South America [syn: camas, camass, quamash, camosh,
         camash]