396 GEOGRAPHICAL BOTANY* 



spiny Mimosa and unparasitic Bromeliacese are common. 

 The latter, with Agave, are frequently the only plants 

 occurring on the calcareous soil; or on other kinds of 

 mountains, the surface is extensively covered with Pro- 

 sopis dulcis and Mimosa. Bronnia spinosa is also cha- 

 racteristic. 



3. Regions froides. 



a. Eastern slope. The determinations of the altitudes 

 of the upper stages of vegetation, e. g. at Oribaza, are in 

 part inaccurate ; thus, according to Liebmann's investiga- 

 tions, the statement that vegetation ceases at 12,500' or 

 13,000' is incorrect ; this portion of the sketch is therefore 

 passed over. This region has yielded 52 Perns, most 

 of which grow upon limestone, and also numerous Orchi- 

 dacese (especially between 7500' and 8000'). 



b. Western slope and high mountains of the plateau. 

 Botanical characteristics wanting. The upper limit to 

 vegetation is situated, according to Galeotti, on Popoca- 

 tapetl, at 11,500', on the Pic of Toluca, at 13,000'. 



c. Most elevated surfaces of the plateau. No botanical 

 characteristics. 



The second and larger section of Hinds's andBentham's 

 work (v. s.), which is, however, not yet perfectly com- 

 pleted, includes the west coast of America from S. Bias 

 (21 32' N. lat.), to Guayaquil (2 30' S. lat.) On this 

 long coast-line the flora is adapted to a moist tropical 

 climate, and the shore covered with a dense forest ; but 

 the plants north and south of Panama are not the same. 

 Nor are the seasons contemporaneous ; the tropical rains 

 commence at Guayaquil in the beginning of the year; 

 towards the north, they gradually occur later, so that at 

 S. Bias they commence at the end of June. They divide 

 the year into two periods of vegetation; the Bay of Choco 

 alone forms an exception, for there atmospheric precipi- 

 tations last from ten to eleven months, producing a vege- 

 tation which is constantly green, and abounding in flowers. 

 The forests of Guayaquil appear to be comparatively poor 

 in forms, because the rainy season there, and with it the 



