Dextrorsal

a.
  1. Turning from the left to the right, in the ascending line, as in the spiral inclination of the stem of the common morning-glory; as, dextrorse vines.

At present scientists predicate dextrorse or sinistrorse quality of the plant regarded objectively; formerly the plant was regarded subjectively, and what is now called dextrorse was then considered sinistrorse.