142 NOTES OF A NATURALIST. 



With only a i^w exceptions, these endemic types 

 appear to have originated in the Andean range, 

 whence some modified forms have descended to the 

 lower country ; several of these, as was inevitable, 

 have been found on the eastern flanks of the great 

 range, and it is probable that further exploration will 

 add to the number ; but it is remarkable that as yet 

 so large a proportion should be confined to Chilian 

 territory. 



Grisebach has fixed the limits of that which he has 

 called the transition zone at the Tropic of Capricorn 

 to the north, and the thirty-fourth parallel of latitude 

 to the south ; but these in no way correspond to the 

 natural boundaries. As I have already pointed out, 

 the flora of the desert zone, extending from about the 

 twentieth nearly to the thirtieth parallel of south 

 latitude, shows a general uniformity in its meagre 

 constituents. It is about the latitude of Coquimbo, 

 or only a little north of it, that the characteristic 

 types of the Chilian flora begin to present themselves, 

 and these extend southward at least as far as latitude' 

 36° south, and even somewhat farther, if I may judge 

 from the imperfect indications of locality too often 

 afforded with herbarium specimens.* 



* One of the difficulties felt by all students of geographical dis- 

 tribution arises from the imperfect or careless indications given both in 

 books and in herbaria, and this is more felt in regard to South America 

 than as to any other part of the world. A very large proportion of the 

 earlier collections bear simply the label " Brazil," forgetting that the 

 area is as great as that of Europe. In other cases local names of places, 

 not to be found on maps or in gazetteers, embarrass the student and 

 weary his patience. It is mainly from Darwin that naturalists have 

 learned that geographical distribution is the chief key to the past history 

 of the earth. 



