The Collaborative International Dictionary of English v.0.48:

Sparse \Sparse\, a. [Compar. Sparser; superl. Sparsest.] [L.
   sparsus, p. p. of spargere to strew, scatter. Cf. Asperse,
   Disperse.]
   1. Thinly scattered; set or planted here and there; not being
      dense or close together; as, a sparse population.
      --Carlyle.
      [1913 Webster]

   2. (Bot.) Placed irregularly and distantly; scattered; --
      applied to branches, leaves, peduncles, and the like.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sparse \Sparse\, v. t. [L. sparsus, p. p. of spargere to
   scatter.]
   To scatter; to disperse. [Obs.] --Spenser.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "sparse":
   almost unheard-of, at a premium, broadcast, cheeseparing, chinchy,
   chintzy, diffuse, discrete, dispersed, dispread, disseminated,
   dissipated, distributed, exiguous, in short supply, inappreciable,
   infrequent, insignificant, limited, little, meager, miserly,
   niggardly, not much, occasional, out of print, out of season,
   out of stock, piddling, poor, rare, scant, scanty, scarce,
   scattered, scrimp, scrimping, scrimpy, seldom met with,
   seldom seen, skimp, skimping, skimpy, slim, slow, spare, sparing,
   sporadic, spotty, spread, spread out, sprinkled, stingy,
   straggling, straggly, strewn, strown, thin, tight, uncommon,
   unfrequent, unique, unusual, widespread