This genus has the carpels irregularly disposed in a head like the two preceding genera, but it is readily distinguished from them by the absence of involucral bracts. Three species are described, from Peru and Chili.

1. P. flexuosa. - An elegant annual with slender stems about 1 foot high, bipinnatifid pilose petiolate leaves, and showy lilac-purple flowers on long slender peduncles.