INDEX. 345 



Panama. Communication by canal or railroad across the Isthmus of Panama 

 discussed, ii. 319. 



Paramo, a mountainous region in South America so called, i. 105 ; its 

 climate and vegetation, i. 105, ii. 269. 



Pastoral life almost unknown to the original inhabitants of America, i. 13. 



Plants, physiognomy of, essentially distinct from a botanical arrangement, ii. 

 14, 17, 208 ; is the principal element in the characteristic aspect of 

 different portions of the earth's surface, 16 ; about sixteen different 

 forms of plants enumerated, which are chiefly concerned in determining 

 the aspect of Nature, 18 ; Palms, 20 ; Plantains or Bananas, 21 ; 

 Malvaceae and Bombacese, 22; Mimosas, 22; Heaths, 23; Cactuses, 

 24 ; Orchidese, 24 ; Casuarineae, 25 ; Coniferse, 25 ; Pothos, 26 ; 

 Lianes, 26; Aloes, 27; Grasses, 27; Ferns, 28; Liliacese, 28; 

 Willows, 28 ; Myrtaceas, Melastomacese, and Laurinese, 29 ; number of 

 species contained in herbariums, 97 ; points of view in which the laws 

 of the geographical distribution of plants may be regarded, 102 ; con- 

 jectures as to the whole number of species on the globe, 119 ; more than 

 half the number of species are probably yet unknown, 121 ; heat deve- 

 loped during inflorescence, 175 ; general remarks on a physiognomic 

 classification, 205. 



Pothos, ii. 26, 175. 



Uuina (or fever bark), ii. 267. 



Roads, old Peruvian, of the times of the Incas, ii. 270. 

 Rotiferse, their revivification, ii. 45. 



Sahara (African desert) composed of several detached basins, i. 114. 



Sand-spouts a phenomenon characteristic of the Peruvian Sand Desert, i. 183. 



Sargasso, Mar de ; its geographical position discussed, i. 63 ; is the most 

 remarkable assemblage of plants of a single species yet known on the 

 globe, i. 64. 



Schomburgk. Travels of the brothers Robert and Richard Schomburgk im- 

 portant in many respects in regard to the physical geography of Guiana 

 and the bordering countries, i. 178, 197, 236, 250. 



