The Monopsis genus consists of 16 species, all of which are indigenous to South Africa where they can be found from Namaqualand to the southern Cape, east to KwaZulu-Natal and north to Limpopo.

Monopsis decipiens, synonymously known as Lobelia decipiens and commonly known as Brother Oneye or Butterfly Monopsis in English and Skoenlapperplant in Afrikaans, is a South African indigenous annual found growing in the Eastern Cape, Free State, Gauteng, KwaZulu-Natal, Limpopo and Mpumalanga provinces. From early spring, through to late summer or early winter it produces gorgeous blue, purple and yellow flowers.