sinistrorse (adj.) Look up sinistrorse at Dictionary.com
1856, a word wanted by the botanists to describe the direction of spiral structures in nature, from Latin sinistrorsus "toward the left side," from sinister "left" (see sinister) + versus "turned," past participle of vertere "to turn," from PIE root *wer- (2) "to turn, bend." It was paired with dextrorse but confusion over what was the proper point of view to reckon leftward or rightward spiraling prevented the word being as useful as it might have been.