The Collaborative International Dictionary of English v.0.48:

Nodular \Nod"u*lar\ (n[o^]d"[-u]*l[~e]r; 135), a. [Cf. F.
   nodulaire.]
   1. Of or pertaining to a nodule or knot.
      [1913 Webster]

   2. Having nodules or in the form of a nodule or knot.
      [PJC]

WordNet (r) 3.0 (2006):

nodular
    adj 1: relating to or characterized by or having nodules;
           "Nodular vaginitis"
    2: having nodules or occurring in the form of nodules; "nodular
       ores" [syn: nodular, nodulated, noduled]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "nodular":
   burled, gnarled, gnarly, knobbed, knobbly, knobby, knoblike,
   knotted, knotty, knurled, knurly, lumpy, nodal, noded, nodiform,
   nodose, nodulated, noduled, nubbled, nubbly, nubby, studded,
   torose, tubercular, tuberculous, tuberose, tuberous