The Collaborative International Dictionary of English v.0.48:

Aciculate \A*cic"u*late\, Aciculated \A*cic"u*la"ted\a. (Nat.
   Hist.)
   (a) Furnished with acicul[ae].
   (b) Acicular.
   (c) Marked with fine irregular streaks as if scratched by a
       needle. --Lindley.
       [1913 Webster]

WordNet (r) 3.0 (2006):

aciculate
    adj 1: related to plants or animals or crystals having aciculae
           or needlelike parts