sinistrorse

from WordNet (r) 3.0 (2006)

sinistrorse
    adj 1: spiraling upward from right to left; "sinistrorse vines"
           [syn: {sinistrorse}, {sinistrorsal}]

from The Collaborative International Dictionary of English v.0.48

Sinistrorse \Sin"is*trorse`\, a. [See {Sinistrolsal}.]
   Turning to the left (of the spectator) in the ascending line;
   -- the opposite of dextrorse. See {Dextrorse}.
   [1913 Webster]