The Collaborative International Dictionary of English v.0.48:
Antrorse \An*trorse"\ ([a^]n*tr[^o]rs"), a. [From L. ante + versun turned; apparently formed in imitation of retrorse.] (Bot.) Forward or upward in direction. --Gray. [1913 Webster]WordNet (r) 3.0 (2006):
antrorse adj 1: bent or curved forward or upward; "a plant having antrorse hairs on the stem" [ant: retrorse]