Paraguay has a depauperate aroid flora with only 16 species, including two species of Anthurium . Argentina has 17 species, including only one Anthurium , A. paraguayense Engl. That species ranges north to Bolivia and southern Brazil. Uruguay and Chile have no Anthurium  (indeed Chile has only the pantropical genus Pistia ) and Uruguay has only four species in three genera). In contrast to the northern hemisphere where several genera, including Arisaema and Lysichiton , range well north of 45 degrees latitude, few Araceae range very far into temperate South America. The southernmost is Pistia , found at 35 degrees latitude in the basin of the Río de la Plata near Buenos Aires.

Sections of the genus Anthurium are not equally distributed. The sectional classification discussed here, somewhat modified from that of either Schott (1860) or Engler (1906) and is outlined by Croat & Sheffer (1983).

Some sections, such as section Pachyneurium , are widespread, ranging throughout most of the range of the genus, with the exception of the wettest part of the range, such as in northwestern Colombia. Most members of the section, especially series Pachyneurium , are most common in areas of seasonally dry forest. The center of diversity for sect. Pachyneurium  is in Ecuador, where 36 species occur, and in Peru with 28 species. These countries are also the centers of endemism with 23 and 13 species respectively. Central America is a second center of diversity for sect. Pachyneurium , especially Costa Rica and Panama, with 23 and 22 species (seven and five species endemic) respectively (Croat, 1991). A portion of this section, including all the cordate species, is restricted to Costa Rica and Panama. Another group, series Multinervia , is nearly restricted to Ecuador with only a few outlying species occurring in Colombia (A. carchiense Croat, A. napaeum Engl., and A. narinoense Croat) or Peru (A. soukupii  Croat and A. ottonis K. Krause).

Section Calomystrium is also widespread, but with the vast majority of its species occurring between Costa Rica, Venezuela and Peru, especially at middle elevations on both slopes of the Andes. A significant percentage of the species, perhaps as much as 50 percent is new to science. The percentages of new species are particularly high in Panama, with 15 of 18 species in the section new to science (Croat, 1986b). The percentages in South America, especially in Colombia where the diversity is greatest, could be as high or higher.

Section Porphyrochitonium has a range similar to that of sect. Calomystrium, and is well represented in Panama with fifty species,but with an even greater concentration in northwestern South America, especially in the wettest forest types at lower elevations. It is particularly well represented in pluvial tropical forest and pluvial premontane forest in Chocó Department of Colombia. For example, 27 species are already known from one small area at Bajo Calima near Buenaventura in the Department of Valle, in transitional premontane pluvial forest. Relatively few species in the section occur in the Amazon basin. Most of the species in the group are new to science. Because of their generally similar appearance, the species are easily overlooked or even mixed by collectors. Probably no section has such a high percentage of species new to science, perhaps owing to their inconspicuous nature (by aroid standards). For example in Panama, 39 taxa (of a total of 80 new taxa described) are members of sect. Porphyrochitonium . The greatest concentration of section Porphyrochitonium is on the Pacific coast of Colombia most appear to be endemic and undescribed. Schott (1860) described only one member of the section, A. scherzerianum , and Engl. (1906) described only 17 additional species while Sodiro (1901a, 1901b,1902, 1903a, 1903b, 1904, 1905a, 1905b, 1906, 1907, 1908a, 1908b) described only 12 species. Though most of the species of