subfamily Pothoideae , tribe Anthurieae . While these disparate placements have no impact on the taxonomy of the genus, it points out the need for further comparative studies between different related genera.

The genus Anthurium is the largest genus in the family andadmittedly, the margin of error in estimating the number of species in this genus is great. Indeed, the margin of error in estimating the number of species existing for Anthurium and Philodendron , the two largest genera in the family, is greater than the total number of all other species in all other neotropical genera combined. While the number of species of Anthurium in Central America (221 spp.) and some parts of South America, e. g. Venezuela (68 species including seven varieties or subspecies), the Guianas, the Amazon basin, and Paraguay, is well known, other areas, especially eastern Brazil and the Andean region of western South America are doubtful. Mayo has produced a checklist for Brazil containing a total of about 100 species, eight of which are new to science. Still, owing to the taxonomic uncertainty of many species of section Urospadix , a complex group of species which are difficult to separate, the total is likely to be higher than that projected by Mayo.

It is in the Andean region of the continent where specific counts of species are most difficult to obtain. While a few areas, notably, the departments of Antioquia and Cundinamarca as well as the region of Popayán in the department of Cauca, have had many species described and probably even have a number of species (especially at the higher elevations) which must be placed in synonymy, many regions were poorly collected prior to Schott's or Engler's revisions, and thus have few species described. Interestingly, these same areas, notably those along the Pacific slope of western Colombia, probably are the most species-rich. For this reason, substantial numbers of new species exist. In some areas which have now been well collected, such as the region of the lower Calima River basin, a region commonly referred to as "Bajo Calima," the majority of species appear to be new to science. The region is largely a transition zone between tropical wet forest and pluvial forest and has yielded, so far, 133 species including 63 species of Anthurium and 40 species of Philodendron , with only a few species yet to be determined and most appearing to be new to science. The Pacific slope also appears to have a high rate of endemism, especially between different life zones and at different elevations. For example, in the department of Nariño, three study sites, all located relatively near one another and all located within a Premontane Forest life zone (according to the Colombian life zone map), contained relatively few species which were shared between sites (Croat, 1992).

Probably regions of pluvial forest, which is restricted to northwestern South America, will prove to be the most species-rich of all. Some parts of this life zone, especially the area south of Quibdó, have been relatively well collected, but the material has not yet been analyzed for a determination of its species diversity.

The situation in Ecuador is even more complex regarding exact numbers of species, especially in Carchí and Esmeraldas Provinces in northwestern Ecuador. Much of Ecuador is probably as rich per unit area as the Pacific slope of the Colombia. Both slopes of the Andes in Central Ecuador in Imbabura, Pichincha, Los Ríos and Cotopaxi, Bolívar, Tungurahua, Chimborazo and Cañar, especially at middle elevations on the Pacific slope and at all but the higher elevations on the Amazonian slope, are rich in species. The same is true of the Amazonian slopes of Loja and in the principally lowland provinces of the so called "Oriente," Sucumbios, Napo, Pastaza, Morona-Santiago and Zamora-Chinchipe. Renner et al, (1990) report 32 species for this region but the actual number is certainly much higher. Much of the middle