No. 416.] REVIEWS OF RECENT LITERATURE. 691 
number of species to be found as we pass from the German Ocean 
and along the Baltic to the Gulf of Bothnia. There is a steady 
reduction in the saltness of the water in this direction until at 
last it is almost imperceptible. Moreover, the east and west sides 
of the Baltic have differing degrees of salinity, and sudden changes 
in this, as also in the temperature, are produced by winds, conditions 
quite unfavorable to the existence of most marine algz; hence the 
poverty of the flora. 
Two elements appear to compose the flora, an Atlantic and an 
Arctic, but without any sharp division line. Four species, one of 
them new, Ascocyclus affinis, are considered endemic, thirty-five are 
. characteristically Atlantic, seventeen characteristically Arctic. Most 
of the species appear in somewhat reduced or depauperate forms, in 
comparison with normal conditions. This is not the case with the 
green alge, however, which are fully as well developed as elsewhere : 
not unnaturally, as the green algz are largely fresh-water plants, the 
red and the brown being specially marine. Asin the Arctic regions, 
Some species cover considerable areas of bottom in loose-lying 
Panes, not attached to any substratum, new growth continually 
forming as the old decays. These detached individuals are uni- 
formly sterile, as is the case in the Arctic Sea, and also with the 
s bna of By ie in the Atlantic. Green alga: are 
Niel Sai littora region, brown in the lower littoral, 
à al, in about the same proportions as in the 
Atlantic. 
i mai a number of illustrations, mostly habit illustrations, 
iiio 2 a "ber of forms of Fucus vesiculosus, and transitions 
fie site since names have been given these forms, it is 
eS to illustrate them, but it is doubtful if they can be 
Saini s all well defined. It is usual to include under 
mile d all dicecious forms with vesicles, as well as those that 
he M ht to have vesicles. It is not unlikely that more 
ae pecies may be here included, but we are not yet in a 
Position to draw the lines. 
s : in Swedish, which is perhaps natural under the cir- 
S ot its issue, but like Kjellman's work previously noted, 
easy of use by the majority of botanists. 
cumsta 
itis n 
(Børgesen, F, Fr 
of the Feröes. 
Sen's paper on th 
eshwater Algæ of the Færöes. From the Botany 
Copenhagen, 1901.) Together with Mr. Børge- 
€ algz, there are printed E. Warming's * Historical 
