A synopsis of Costa Rican Ruellia (Acanthaceae), with descriptions of four new species

We describe four new species of Ruellia from Costa Rica; three from the Osa Peninsula, Puntarenas province (R. exilis, R. mira, R. odorata), and one from the southwestern corner of San José province (R. norvegigratiosa). Ruellia matagalpae is reported as a new record for the country. New combinations are made in Ruellia for the two Costa Rican species of Blechum (R. blechum and R. costaricensis). Three species are reduced to synonymy, and another species is considered doubtfully worthy of recognition. Notable range extensions are reported for two species. Corollas and fruits of all 22 Costa Rican species of Ruellia are shown and compared as easily used identification aids. An informal guide to species groups and a dichotomous key to the 22 species are presented.