The Collaborative International Dictionary of English v.0.48:

Immortelle \Im`mor*telle"\, n.; pl. Immortelles. [F. See
   Immortal.] (Bot.)
   A plant with a conspicuous, dry, unwithering involucre, as
   the species of Antennaria, Helichrysum, Gomphrena, etc.
   See Everlasting.
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The Collaborative International Dictionary of English v.0.48:

Everlasting \Ev`er*last"ing\, n.
   1. Eternal duration, past or future; eternity.
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            From everlasting to everlasting, thou art God. --Ps.
                                                  xc. 2.
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   2. (With the definite article) The Eternal Being; God.
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   3. (Bot.) A plant whose flowers may be dried without losing
      their form or color, as, the pearly everlasting
      (Anaphalis margaritacea), the immortelle (Xeranthemum
      anuum) of the French, the cudweeds, etc.
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   4. A cloth fabric for shoes, etc. See Lasting.
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WordNet (r) 3.0 (2006):

immortelle
    n 1: mostly widely cultivated species of everlasting flowers
         having usually purple flowers; southern Europe to Iran;
         naturalized elsewhere [syn: immortelle, Xeranthemum
         annuum]