NATURAL AREAS AND REGIONS 



677 



cane grass, cana brava, Gynerium (Rio 

 Beni, Bolivia). These areas sometimes 

 extend back a mile before they meet 

 the forest. On the Rio Negro, the 

 water and the forest meet, as they do 

 on many smaller streams here and there 

 through the basin. Another type of 

 differentiation in the vegetative areas 

 depends on the flood plain — the ter- 

 ritory between low and maximum high 

 water recorded over many years (var- 

 zias) and the ten-a firma, land not 

 subject to the annual inundations, 

 except under exceptional circumstances. 

 Wooded portions of the varzias are 

 "ygapos" or "igapos," while those 

 dominated by the great herbaceous 

 stems of the giant arum (Montrichardia 

 arhorcscens) are "aningas." The great- 

 est differentiation between the different 

 areas is found, generally speaking, on 

 the outer edge of the basin, where the 

 streams begin and the mountains act as 

 barriers and species preservers. In 

 fact these peripheral regions, especially 

 in the west are veritable nurseries for 

 new species, each mountain valley 

 often acting as a specialist for distinct 

 types. As the streams unite and form 

 larger streams and these unite to form 

 still greater arteries, the differentiation 

 between regions becomes less and less 

 until the lower Amazon is in some re- 

 spects a huge jumble of the animal and 

 vegetable life from all its tril)utaries, 

 unless special factors of some kind have 

 interfered to prevent a contribution. 

 So the farther away from the delta, in 

 general, the more varied the natural 

 life. 



The high altitudes are the home of 

 the semi-domestic llama and alpaca 

 and their wild relatives the vicuna and 

 guanaco. Chinchillas, viscachas and 

 the cavia (guinea pigs) abound in some 

 parts, while in the highest regions the 

 condor makes its home. Plant life in 

 the Andes reaches a height of over 15,000 

 ft. (4600 m.). Wiry "ichu" grass (Stipa), 

 Festuca and Calamagroslis, rushes, a 

 few hardy and peculiar bromeliads, 

 such as Pourretia, 10 to 12 ft. tall with a 

 sentinal-like habit, and mounds of moss- 



like "yareta," largely Azorellas and 

 Aretiastrums, are characterisic forms. 

 This whole upper region is extremely 

 bleak, barren, stony and full of moors. 

 There are no woody plants, except here 

 and there patches of tola (mostly a 

 composite, Lepidophyllimi) which some- 

 what recall the sagebrush of western 

 North America. Little carpets of star- 

 flowered alpines (Gentians, Cerastiums, 

 Perezias) and the dandelion-like WcTne- 

 rias hug the sheltered slopes, especially 

 near water. Clumps of Opuntia dot the 

 desolation with little thorny domes. 

 Between 11,000 and 12,000 ft., the van- 

 guard of the forest begins to appear as 

 occasional bushes and small trees 

 {Polylepis, Buddlcia) and these often 

 abound with parasitic Loranthaceae. 

 Lupines, bushy yellow-flowered Calce- 

 olarias, Senecios, Polypodium ferns, 

 lycopodiums (L. robustum), Baccharis, 

 border the high water boundaries of the 

 small streams. Wernerias become plen- 

 tiful. Between 9000 and 10,000 ft., 

 chaparral (ceja) shubbery is present, 

 in quantity and large variety, Rubus, 

 Berheris, Ribes, Calceolaria, Barnadesia, 

 Viburnum, Tibouchina, Fuchsia, and 

 Clematis are common representatives 

 of the woody types, while herbaceous 

 plants are found in such typical form.s as 

 Anemone, Tropaeolum, Crotalaria, Bys- 

 tropogon, Solanum, Gerardia, Liabum, Bo- 

 marea, Commelina, Gunnera, Nicotiana, 

 and Tagetes. Among the perchers, or epi- 

 phytes, small Tillandsias, climbing Pol- 

 ypodium ferns, various peppers (Pepero- 

 mias) and orchids (Odontoglossum) are 

 common as forerunners of the great 

 epiphytic plant world, miles away and 

 thousands of feet nearer the sea level. 

 Both purple and yellow dodders {Cus- 

 cuta) furnish evidence of the aggres- 

 siveness of the parasitic plants, as they 

 enmesh and wind about their hosts. 

 Climbing composites {Mutisia) and 

 Clematis ramble over the bushes, while 

 above the chaparral area, the grassy 

 slopes are colonized with Bromeliads 

 {Pitcairnia, Puya), red-flowered ground 

 orchids (Epidendrmn) and Salvias. 

 Lichens {Usnea, etc.) are prominent on 



