GENERAL DISTRIBUTION. 43 



boulders of rock, at an elevation of 15,770 feet. 

 At a lower elevation, the Orchidece enliven the 

 clefts of the wildest rocks, and the trunks of 

 gigantic trees. " This form," says Humboldt, 

 " to which the Vanilla belongs, is distinguished 

 by its bright green succulent leaves, by its 

 flowers of many colours, and strange and curious 

 shape, sometimes resembling that of winged in- 

 sects, and sometimes that of the birds, which are 

 attracted by the perfume of the honey vessels. 

 Such is their number and variety, that to men- 

 tion only a limited district, the entire life of a 

 painter would be too short for the delineation of 

 all the OrchidecB which adorn the recesses of the 

 deep valleys of the Andes of Peru." 



In a note, the same illustrious philosopher 

 adds, " While in the temperate and cold zones 

 there are only terrestrial Orchidea, that is, such 

 as grow on and close to the ground, tropical 

 countries possess both forms, namely, the terres- 

 trial and the parasitic, which grow on the trunks 

 of trees. To the first-named of these two divi- 

 sions belong the tropical genera, Neottia, Cra- 

 nichis, and most of the Habernarias. "We have 

 also found both forms growing as alpine plants, 

 on the slopes of the chain of the Andes of New 

 Granada and Quito. Of the parasitical Orchi- 

 deae (Epidendrece), we have found Masdevallia 

 uniflora at about 10,230 feet, English measure ; 

 Cyrtochilum Jlexuosum at about 10,100 feet ; and 

 Dendrobium aggregatum at about 9,480 feet. Of 



