Question: Which has more species, Calendula or Purshia?

Context paragraphs:
Calendula arvensis: Calendula arvensis is a species of flowering plant in the daisy family known by the common name field marigold.  It is native to central and southern Europe, and it is known across the globe as an introduced species.

Calendula: Calendula ( ), is a genus of about 15–20 species of annual and perennial herbaceous plants in the daisy family Asteraceae that are often known as marigolds.  They are native to southwestern Asia, western Europe, Macaronesia, and the Mediterranean.  Other plants are also known as marigolds, such as corn marigold, desert marigold, marsh marigold, and plants of the genus "Tagetes".

Purshia stansburyana: Purshia stansburyana is a species of flowering plant in the rose family known by the common name Stansbury's cliffrose.  It is native to the southwestern United States and northern Mexico, where it grows in woodlands, desert, and plateau habitat.  It often grows anchored on cliffs and prefers rocky, granular soils, especially limestone.

Purshia: 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.

Purshia mexicana: Purshia mexicana is a species of perennial flowering small tree in the rose family known by the common name Mexican cliffrose.  It is native to western-northern Mexico, the region of the Sierra Madre Occidental cordillera.

Calendula maritima: Calendula maritima, known as the sea marigold and trailing calendula, is a very rare species from the family of Asteraceae.  Some scientists regarded it as "Calendula suffruticosa" subspecies "maritima".

Purshia glandulosa: Purshia glandulosa is a species of flowering plant in the rose family known by the common names antelope bitterbrush, desert bitterbrush, Mojave antelope brush.

Supporting paragraphs: Calendula Purshia
Answer: Calendula