240 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH Ser. 
around these islands are almost constantly from the southeast, 
the fern flora should be most closely related to that of the cen- 
tral and southern part of South America. Such is not the case, 
however, for outside of fifteen species which are of wide distri- 
bution, the fern flora shows nearly as strong affinities with that 
of Mexico as it does with that of South America. There are 
on the islands fifty-four species common to Mexico and fifty-six 
to South America. Moreover, the majority of the latter belong 
only to the northern part of the continent. 
Devices for wind dissemination are not common on the seeds 
of Galapagos plants, the Compositae being the only one of the 
larger families which has this character pronounced to any 
extent. 
Oceanic Currents 
The northern islands of the group, viz. Abingdon, Bindloe, 
Culpepper, Tower, and Wenman, lie in the direct path of the 
Panama current, and the water surrounding them is several 
degrees warmer than that around the southern islands, which 
are bathed by the Humboldt current. If oceanic currents were 
an important factor in the transport of seeds to the Galapagos, 
those islands which are washed by the Panama current should 
be more closely related botanically to the Mexican and Central 
American regions than the islands lying in the Humboldt 
current; and the latter islands, on the other hand, should have a 
flora more closely related to that of the western coast of South 
America. Furthermore, the several islands of each group 
should have a larger floral element common among themselves 
than with any of the islands of the other group. The following 
table shows the percentages of floral relationships between the 
islands of the northern group, as well as their relationships with 
some of the more important islands of the southern group. 
FLORAL RELATIONSHIPS OF NORTHERN ISLANDS 
e : gE 
MW esta yesh tes as can [oe al eee Fa 
& 2 E 1S = & S ES 
Soy esed hte a ae E: SUNG Seen ee 
Abingdon..... Ra 83.1 a ne ane GOn3))| 10722 
Bindloems.r.. S573 eHOO Wh Me oy. 68.5 | 61 
MRO WEL Aecarche 72.7 | 68.1 | 48.4 | 48.4 tye 2AM EOL ao 
Wenman..... PSSc5,4 OO i $5.7] 35.7 | 38:6)}).50 38.5 
