IV. 
INTRODUCTION. 
25 
River, N. C., and at Key "West, are all the evidence we at present possess of the 
existence of that type of form on the North American shore. Plocamium coccineum , 
so abundant in Europe, and which is also widely dispersed in the Southern Ocean, 
extending from Cape Horn eastwards to New Zealand, has not that I am aware of 
been found on the American Atlantic coast, where its place seems taken by the 
equally brilliant Rliodymenia cristata. Ceramium rubrum is as common on the 
American as on the European coast, and many of the other common American 
Rhodosperms are natives of both continents. 
The Green Algae ( Chlorosperms ) are still more alike ; but several of the Ameri- 
can Cladophoree (not yet fully explored) seem to be peculiar. Codium tomentosum , 
which is common to the shores of Europe from Gibraltar, in lat. 36°, to Orkney 
in lat. 60°, and perhaps further north, has yet been found only on the Florida Keys, 
(lat. 24°). Judging from its distribution in other parts of the world, particularly 
in the Pacific and Southern Oceans, one would have expected to find it all along 
the East coast of North America. 
Perhaps it would be premature to indicate regions of Algge into which the 
Eastern and Southern shores of the North American states may be divided, a few 
points only having as yet been carefully explored. Halifax Harbour, Massachusetts 
Bay, Long Island Sound at several points from Greenport to New York, New York 
Harbour, and the neighbourhood of Charleston, S. C., are the chief points at which 
the materials for this essay have been collected on the East coast. Our knowledge 
of southern Algas is at present derived chiefly from a partial examination of the 
Florida Keys, by Dr. Wurdemann, Professor Tuoiney, Dr. Blodgett and myself. I 
think it probable, however, that future researches will indicate four regions of dis- 
tribution, as follows : — 
1st. Coast north of Cape Cod, extending probably to Greenland. Among 
the characteristic forms of this region are the great Laminarias, particularly 
L. Longicruris , one of the largest Algae on the coast, and Agarum Turner i and 
pertusum. Several of the rarer Fucacese seem also to be confined to this district. 
One of the most abundant and characteristic species of this tract is Rliodymenia 
cristata , which has not to my knowledge been found farther south than Cape 
Cod. Specimens said to have come from Staten Island have been shown to me, 
but the evidence on which the habitat of these rests is not satisfactory, and 
none of the Brooklyn and New York Algologists (a numerous and indefatigable 
band) have yet detected the plant in their harbour. Ptilota plumosa is also a 
plant of this region, the only species (as far as I know) that is met with in 
Long Island Sound being P. sericea , Gnu Rhodomelce are more abundant here 
than in the Sound, but are not limited to this division ; Odonthalia (a peculiarly 
northern form) has been seen only at Llalifax. Dumontia ramentacea , so abun- 
dant at Iceland, is found also at Newfoundland, and near Halifax, where I 
gathered it plentifully. Of this plant I possess a single specimen, picked up by 
Miss Frothingham on Rye Beach, New Hampshire. All the species I have men- 
tioned are Arctic forms confined in the European waters to very high latitudes, 
and all appear to vegetate nearly as far south as Cape Cod, to which limits they 
are almost all confined. The Marine flora of this region as a whole bears a 
VOL. in. art. 4. 
E 
