The Collaborative International Dictionary of English v.0.48:

Myrtle \Myr"tle\ (m[~e]r"t'l), n. [F. myrtil bilberry, prop., a
   little myrtle, from myrte myrtle, L. myrtus, murtus, Gr.
   my`rtos; cf. Per. m[=u]rd.] (Bot.)
   A species of the genus Myrtus, especially Myrtus
   communis. The common myrtle has a shrubby, upright stem,
   eight or ten feet high. Its branches form a close, full head,
   thickly covered with ovate or lanceolate evergreen leaves. It
   has solitary axillary white or rosy flowers, followed by
   black several-seeded berries. The ancients considered it
   sacred to Venus. The flowers, leaves, and berries are used
   variously in perfumery and as a condiment, and the
   beautifully mottled wood is used in turning.
   [1913 Webster]

   Note: The name is also popularly but wrongly applied in
         America to two creeping plants, the blue-flowered
         periwinkle and the yellow-flowered moneywort. In the
         West Indies several myrtaceous shrubs are called
         myrtle.
         [1913 Webster]

   Bog myrtle, the sweet gale.

   Crape myrtle. See under Crape.

   Myrtle warbler (Zool.), a North American wood warbler
      (Dendroica coronata); -- called also myrtle bird,
      yellow-rumped warbler, and yellow-crowned warbler.

   Myrtle wax. (Bot.) See Bayberry tallow, under Bayberry.


   Sand myrtle, a low, branching evergreen shrub (Leiophyllum
      buxifolium), growing in New Jersey and southward.

   Wax myrtle (Myrica cerifera). See Bayberry.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

bog \bog\ (b[o^]g), n. [Ir. & Gael. bog soft, tender, moist: cf.
   Ir. bogach bog, moor, marsh, Gael. bogan quagmire.]
   [1913 Webster]
   1. A quagmire filled with decayed moss and other vegetable
      matter; wet spongy ground where a heavy body is apt to
      sink; a marsh; a morass.
      [1913 Webster]

            Appalled with thoughts of bog, or caverned pit,
            Of treacherous earth, subsiding where they tread.
                                                  --R. Jago.
      [1913 Webster]

   2. A little elevated spot or clump of earth, roots, and
      grass, in a marsh or swamp. [Local, U. S.]
      [1913 Webster]

   Bog bean. See Buck bean.

   Bog bumper (bump, to make a loud noise), Bog blitter,
   Bog bluiter, Bog jumper, the bittern. [Prov.]

   Bog butter, a hydrocarbon of butterlike consistence found
      in the peat bogs of Ireland.

   Bog earth (Min.), a soil composed for the most part of
      silex and partially decomposed vegetable fiber. --P. Cyc.

   Bog moss. (Bot.) Same as Sphagnum.

   Bog myrtle (Bot.), the sweet gale.

   Bog ore. (Min.)
      (a) An ore of iron found in boggy or swampy land; a
          variety of brown iron ore, or limonite.
      (b) Bog manganese, the hydrated peroxide of manganese.

   Bog rush (Bot.), any rush growing in bogs; saw grass.

   Bog spavin. See under Spavin.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

bogbean \bogbean\ n.
   a perennial plant of Europe and America (Menyanthes
   trifoliata) having racemes of white or purplish flowers and
   intensely bitter trifoliate leaves; often rooting at the
   water margin and spreading across the surface; -- called also
   bog myrtle, water shamrock and marsh trefoil.

   Syn: water shamrock, buckbean, bog myrtle, marsh trefoil.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

bog myrtle
    n 1: perennial plant of Europe and America having racemes of
         white or purplish flowers and intensely bitter trifoliate
         leaves; often rooting at water margin and spreading across
         the surface [syn: water shamrock, buckbean, bogbean,
         bog myrtle, marsh trefoil, Menyanthes trifoliata]