FLORAL AFFINITIES 
417 
southern flora passed over them, for of course southern 
plants penetrated northward just as animals did. Mr. Sereno 
Watson,* for example, in referring to the flora of the small 
island of Guadalupe off the west coast of California, remarks 
that the presence of so many South American types suggests 
that this, and the similar element which characterises the 
flora of California, may be due to some other connection be¬ 
tween these distant regions than the one now existing. He 
expresses the opinion, too, that all the peculiarities in the 
western floras of both continents had a common origin in an 
ancient flora which prevailed over a wide, now submerged 
area, and of whose character the former are the partial 
exponents. 
As regards the question whether the northern plants 
growing in Chile and Argentina can really be regarded as 
indigenous or introduced, Professor Hackel has recently dealt 
with this problem from a new point of view. He shows that 
the species which are either identical with European or North 
American plants, or such as may be considered as varieties or 
sub-species of them, increase rather than diminish as we go 
further south. Thus he records fifty-one plants from 
southern Patagonia and Tierra del Fuego belonging to this 
group, which he regards as undoubtedly indigenous to these 
countries. Thirty others may possibly have been introduced 
by man. Professor Hackel thinks that their southward 
advance could only have taken place step by step on a land 
surface. If these plants had passed across Central America 
and along the Andes, we should find relict colonies of the 
species, or at least their modified descendants, scattered on 
their route of migration. Only very few of such occur in 
Bolivia, Peru and Ecuador, and these have the appearance 
of having reached these localities from the south rather than 
from the north. When we examine the composition of this 
remarkable flora in the Magellan district, we notice, according 
to Professor Hackel,f that the majority of the species belong 
to the grasses (Gramineae) and the sedges (Cyperaceae). The 
dicotyledons only comprise fifteen species. This he believes 
* Watson, Sereno, “ Flora of Guadalupe Island,” p. 112. 
t Hackel, E., “ Flora der Magellanslander,” pp. cxi—cxv. 
L.A. 
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