The Collaborative International Dictionary of English v.0.48:

Goat's beard \Goat's beard\, goatsbeard \goatsbeard\n. (Bot.),
   A weedy European annual with yellow flowers, of the genus
   Tragopogon; -- so named from the long silky beard of the
   seeds. One species is the salsify or oyster plant; it is
   naturalized in US.

   Syn: meadow salsify, shepherd's clock, Tragopogon
        pratensis.
        [1913 Webster + WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Salsify \Sal"si*fy\ (?; 277), n. [F. salsifis.] (Bot.)
   See Oyster plant
   (a), under Oyster.
       [1913 Webster]

WordNet (r) 3.0 (2006):

salsify
    n 1: edible root of the salsify plant [syn: salsify, oyster
         plant]
    2: Mediterranean biennial herb with long-stemmed heads of purple
       ray flowers and milky sap and long edible root; naturalized
       throughout United States [syn: salsify, oyster plant,
       vegetable oyster, Tragopogon porrifolius]
    3: either of two long roots eaten cooked