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NATURALIST'S GUIDE TO THE AMERICAS 



luxuriant in aspect. The trees are more 

 uniformly and compactly branched. 

 In its upper stages the trees become 

 strikingly rounded and densely bushy, 

 and frequently occur in park-like for- 

 mation. More often however the 

 densely massed low trees pass imper- 

 ceptibly into a zone of shrubs equally 

 dense. The upper mountain-forest, and 

 the plateau savannas and paramo as 

 well, are of peculiar interest because of 

 the double origin of the forms of life 

 that characterize them. There may be 

 here the same types of life seen in the 

 lowland and lower mountain-forests, 

 the same families of trees, of herbs and 

 of epiphytes, but usually or always in 

 special upper-mountain species. With 

 these there are many other types of 

 life not found at all in the lowland and 

 lower forests but which are genera 

 and families which belong characteris- 

 tically to the cooler parts of the earth, 

 the Temperate zones of the Northern 

 and Southern Hemispheres. Such tem- 

 perate influence is less marked among 

 trees than among shrubs and herbs, 

 although Colombia has its native species 

 of alder and walnut as well as its various 

 shrubby Hypericums, Gaultherias and 

 Vacciniums, and its many herbaceous 

 buttercups, chickweeds, geraniums and 

 violets. A third series of upper Andean 

 plant and animal types, certainly in 

 its origin assignable to one or the other 

 of these groups but now especially 

 pronounced and interesting, contains 

 the types of life now restricted to or 

 mainly developed upon the Andes, 

 genera often divisible into species per- 

 taining to various elevations and to 

 various isolated portions of the moun- 

 tain-system. Among flowering plants 

 this series includes Bomarea, Tropaeo- 

 lum, Monnina, Fuchsia, Calceolaria, 

 Centropogon, Mutisia, and very many 

 others. 



The upper mountain-forest is much 

 more broken into isolated portions, 

 due to breaks in the continuity of the 

 Andean mountain-system, than is the 

 forest of the lower slopes. It is con- 

 tinuous throughout the Central Cordil- 



lera, but in the Western Cordillera 

 becomes isolated upon each of the high- 

 lands already mentioned, while in the 

 Eastern Cordillera it covers a large 

 area from Sumapaz to Ocaiia, with 

 small areas northeast and southeast 

 of Neiva and again far to the northward 

 in the Motillones and the Sierra de 

 Perija. 



This upper mountain-forest and the 

 open areas occurring at the same altitude 

 have been termed the "Temperate 

 Zone" by Dr. Chapman. The chief 

 families of birds are (1) Trochilidae, 

 (2) Tanagridae, (3) Fringillidae, (4) 

 Tyrannidae, (5) Coerebidae. 



This cool forest "includes a few 

 mountain forms of mammals derived 

 from tropical relatives, as the mountain 

 paca, the mountain opossum and the 

 mountain brocket deer, also by forms 

 derived from the southern Andes, as 

 the spectacled bear (Tremarctos) and 

 the peculiar marsupial Caenolestes; also 

 by forms of North American affinity as 

 weasels (Mustela), rabbits (Sylvilagus} 

 and shrews (Blarina). It has various 

 peculiar genera of rodents as Thomaso- 

 mys, Microxns, Chilomys, and Aepe- 

 omys." 



While on the mountain-slopes seasons 

 are less distinctly marked than on the 

 lowland and because of topography 

 are subject to much modification, the 

 rains tend to occur mostly in two rainy 

 seasons lasting each from an equinox 

 to a solstice. Mid-March to mid-June 

 and mid-September to mid-December 

 are likely to be wet, and mid-June to 

 mid-September and mid-December to 

 mid-March dry or rather dry, at middle 

 elevations of the Andes. 



In many parts of Colombia, especially 

 on the western slope of the Eastern 

 Cordillera in Santander and Cundina- 

 marca, on the eastern slope of the Cen- 

 tral Cordillera in Antioquia and Tolima 

 and on its western slope in Antioquia, 

 Caldas, El Valle and El Cauca, the 

 lower mountain-forest has been exten- 

 sively cleared to make room for planta- 

 tions of coffee. The upper mountain- 

 forest has been considerably cleared for 



