 According to José Cuatrecasas, (1986) the genus is an element of Neotropical origin that could have reached the paramos from the southern latitudes of South America; where the primitive arboreal species can be found in the high Andean forest while the most advanced members can be found in the paramos and super-paramos.This reinforces previous theories from Cuatrecasas (1969), who proposed as atavistic characteristics the morphologies present in the arboreal species of high Andean forest.Based on this, Cuatrecasas made a phylogenetic ordination into natural groups or series where the derived species are more diverse and are found at high altitudes.