474 INDEX. 



Panama. Communication by canal or railroad across the Isthmus of 

 Panama discussed, 449. 



Paramo, a mountainous region in -South America so called, 97 ; its 

 climate and vegetation, 97, 414. 



Pastoral life almost unknown to the original inhabitants of America, 

 34. 



Plants, physiognomy of, essentially distinct from a botanical arrange- 

 ment, 235, 236, 369 ; is the principal element in the characteristic 

 aspect of different portions of the earth's surface, 236 ; about six- 

 teen different forms of plants enumerated, which are chiefly con- 

 cerned in determining the aspect of Nature, 237 ; Palms, 238 ; 

 Plantains or Bananas, 239 ; Malvaceae and Bombaceas, 240 ; Mi- 

 mosas, 240 ; Heaths, 240 ; Cactuses, 241 ; Orchidese, 241 ; Casu- 

 arineae, 242 ; Coniferae, 242 ; Pothos, 242 ; Lianes, 243 ; Aloes, 

 243; Grasses, 243; Ferns, 244; Liliaceaa, 244; Willows, 244; 

 Myrtaceae, Melastomaceae, and LaurineaD, 244 ; number of species 

 contained in herbariums, 291 ; points of view in which the laws 

 of the geographical distribution of plants may be regarded, 295 ; 

 conjectures as to the whole number of species on the globe, 306 ; 

 more than half the number of species are probably yet unknown, 

 308 ; heat developed during inflorescence, 346 ; general remarks 

 on a physiognomic classification, 367. 



Pothos, 242, 345. 



Quina (or fever bark), 413. 



Koads, old Peruvian, of the times of the Incas, 415. 

 Rotiferae, their revivification, 255. 



Sahara (African desert) composed of several detached basins, 103.. 



Sand-spouts a phenomenon characteristic of the Peruvian Sand De- 

 sert, 150. 



Sargasso, Mar de ; its geographical position discussed, 68 ; is the most 

 remarkable assemblage of plants of a single species yet known 

 on the globe, 68. 



Schomburgk. Travels of the brothers Robert and Richard Schom- 

 burgk important in many respects in regard to the physical geo- 

 graphy of Guiana and the bordering countries, 148, 160, 189, 

 199. " 



Sleep, summer and winter, of animals, 36, 152, 257. 



Snow, limit of perpetual ; inequality of this limit on the northern and 

 southern declivities of the Himalaya, 92. 



Sorata and Illimani ; their heights above the sea recently corrected. 

 63, 90, 217. 



Steppes and Deserts, characteristics of the European, 26 ; African, 

 26 ; Asiatic, 27 ; South American, 29 ; analogies and contrasts 

 between the steppes and the ocean, 26, 49. 



Strato, his sluice theory, 279. 



Sugar-cane ; of Tahiti, of the West Indies, and of Guiana, 45. 



Tacarigua, Lake of, 25 ; its scenery and vegetation, 43. 



