Luang Prabang prov., Pon Xay distr., Nam Bo village, around point 19°57′23.5′'N 102°26′16.4′'E.
Degraded primary evergreen and semideciduous forest on very steep rocky mountain slopes composed by solid marble like highly eroded limestone at elev. 650-750 m a.s.l.
Giant herb with erect leaves to 5.5 m tall in open rocky slope. Floral bracts brownish to dull purple, flowers yellow. Very common.