62 Rhodora [APRIL 
Is it not more reasonable to take up what is, in reality, the only 
remaining hypothesis—namely, that the coastal plain flora was at 
some time far more extensive around the Great Lakes than it is at 
present, and that this fact was due to the prevalence, in ancient times, 
of conditions favorable to its spread? We may conclude that these 
conditions—which obtain at the present over only very restricted 
areas—represent conditions at one time fairly general everywhere 
between the coastal plain and the farthest outlying extensions of 
its flora. 
SUMMARY OF THE FLORA OF SOME INLAND SAND DEPOSITS. 
Since the coastal plain flora in its inland extensions seems generally 
to be associated with sand deposits, it may be well to glance at the 
localities and vegetation of some dune areas. 
Presque Isle is a big “hook” on the Pennsylvania shore of Lake 
Erie, composed of sand spits, dunes and lagoons. The flora of this 
area contains 439 species, 18 varieties and one hybrid'. About 15 
species are coastal plain types, or offshoots from them. 
Very similar in character are the sands of Indiana, where high dunes, 
bogs, lagoons and old sand spits abound. Here there are about sixty 
coastal plain types and related offshoots. Of somewhat different 
character are the sand deposits of the Illinois River". Here are 
sandy wastes and dunes where little strand or lagoon life is repre- 
sented, with the result that the number of coastal plain species falls 
off to about six. 
If now the plant life of the Nebraska dunes be examined? we find 
that there is not a single species! which might be classed as commonly 
restricted to the coastal plain, although a few, such as Chenopodium 
leptophyllum and Rumex maritimus var fueginus (* R. persicaroides") 
which abound in subsaline regions of the interior, are found on the 
sea-beaches or brackish sands of eastern America. 
1 According to Jennings, An Ecological Survey of Presque Isle, Erie County, 
Pennsylvania, Ann. Carneg. Mus. v, 289—421. 
? See Gleason, Vegetation of the Inland Sand Deposits of Illinois, Bull. Ill. State 
Lab. Nat. Hist. ix, 23-174. 
3See Rydberg, Flora of the Sand Hills of Nebraska, Contrib. U. 8. Nat. Herb. 
iii. 133-203. 
! Rydberg lists Potamogeton Oakesianus from Nebraska, but the report seems doubt- 
ful. 
