Simmons, Bemarks about tlieBelations of the Floras etc. 
187 
few species, is not easily decided, at all events the number of 
forms that stand very near to each other is considerable and 
must be accounted for by assuming a cleaving of the previous 
species within a near p&riod. The species that are found farther 
to the south must have been among the first to leave the pre- 
glacial Polar Sea (or their ancestors have done it). That L. Bo- 
driguezii can have come into the Mediterranean during the ice- 
age is not in the least improbable. Somewhat more difheult it 
is to explain the existence of Laminaria- species at the coast of 
South Africa. 
JPligllaria also is probably a tertiary-polar genus, as it has 
a species common to both northern oceans, and also some way 
enters the Polar Sea. That two species reach south of the Strait 
of Gibraltar does not contend against such an assumption. 
Saccorhiza has a distribution that seems to point to an ori¬ 
gin in the Atlantic, but I am inclined to think, that it too has 
come from the tertiary Polar Sea, together with the otlier La¬ 
minar iean. 
Agarnm, This genus is represented on the whole coast of 
northern America and also on tlie Pacihc coast of Asia, but not 
in the european and asiatic parts of the Polar Sea. As all the 
4 other genera of the Agareae are solelv northpaeihe, there per- 
haps could be some reason for assuming the Bering-Sea-region 
to be their original home, but that would not account for the 
occurrence of Agarum Turneri as far as Grreenland (even on 
the Southern part of the east coast) and the Atlantic shores of 
America. That genus at least must have been tertiary polar 
(cf. Setchell, 48, p. 373). Perhaps also the other genera have 
originated north of Bering Strait, but only been spread within 
a smaller area before they were driven southvvards by the gla- 
ciation. 
That the Lessoniideac are of pacihc origin cannot be doub- 
ted, and most probably they also have had their hrst home in 
the northern parts of that ocean, as most of them are still found 
there. They must have during the iceage passed the war¬ 
mer seas and reached the Southern temperate and antarctic 
waters, where especially Macrocgstis jpgrifera now has a great 
area. 
Among the Alariideae there are forms of so widely diffe¬ 
rent distribution, that’it is hardiy possible to form anv opinion 
about the origin of the whole tribe. Most of them indeed are 
northpaeihe, JEcklonia however is principally distributed in the 
Southern and even in warmer seas. The genus of greatest in- 
terest here is Maria that shows a considerable correspondence 
with Laminaria (cf. Setchell, 48, p. 366), as well in the distri¬ 
bution as in the existence of a great many closely allied forms, 
by some authors classihed as species, by otliers reduced to va- 
rieties. Setchell (48, p. 347) speaks of this eonfusion and gives 
the number of species as 15 or 20. In his fable there are 18 
species (Be Tony has one more, A. musaefolia). I prefer to 
