In this task, you are given a context paragraph, a question based on that and corresponding answer of a question. Your task is to generate supporting fact/knowledge from context paragraph which helps in answering a given question.

Purshia (bitterbrush or cliff-rose) is a small genus of 5-8 species of flowering plants in the family Rosaceae, native to western North America, where they grow in dry climates from southeast British Columbia in Canada south throughout the western United States to northern Mexico. The classification of "Purshia" within the Rosaceae has been unclear. The genus was originally placed in the subfamily Rosoideae, but is now placed in subfamily Dryadoideae. Question: Which one, Purshia or Maihuenia, is a small genus of 5-8 species of flowering plants in the family Rosaceae? Answer: Purshia
Purshia bitterbrush or cliffrose is a small genus of 58 species of flowering plants in the family Rosaceae, native to western North America, where they grow in dry climates from southeast British Columbia in Canada south throughout the western United States to northern Mexico.