Toxicological trivia from September 24, 2014; Adiantum capillus-veneris, the Southern maidenhair fern, black maidenhair fern, and venus hair fern, is a species of ferns in the genus Adiantum with a subcosmopolitan worldwide distribution. It is cultivated as a popular garden fern and houseplant.  Adiantum capillus-veneris grows from 6 to 12 in (15 to 30 cm) in height; its fronds arising in clusters from creeping rhizomes 8 to 27.5 in (20 to 70 cm) tall, with very delicate, light green fronds much subdivided into pinnae 0.2 to 0.4 in (5 to 10 mm) long and broad; the frond rachis is black and wiry. This plant is used medicinally by Native Americans:a)  The Mahuna people use the plant internally for rheumatism; b)  The Kayenta Navajo use an infusion of the plant as a lotion for bumblebee and centipede stings;c) Both previous statements are correct. 

Correct Answer c. Read more in WP.