sin·is·trorse 
(sĭnĭ-strôrs′)
(sĭnĭ-strôrs′)adj.
Growing upward in a spiral that turns from right to left: a sinistrorse vine.
[Latin sinistrōrsus, turned toward the left, contraction of *sinistrōversus : sinistrō, toward the left, from ablative of sinister, left + versus, past participle of vertere, to turn; see wer-2 in the Appendix of Indo-European roots.]