HarPeR: Trip oN WARRIOR AND TOMBIGBEE RIVERS 117 
greater prevalence of Platanus, Betula, Hicoria aquatica, Quercus 
lyrata, Juniperus, Alnus, Onoclea, Aster lateriftorus, Conoclinium, 
Uniola, and Osmunda in the Cretaceous region, and of Populus, 
Pinus glabra, Magnolia grandiflora, Adelia acuminata, Vitis vul- 
pina, Tillandsia, Dianthera, Acuan, Spermacoce, Paspalum mucro- 
natum, Ammannia, and a few others in the Eocene. All of the 
former are species of more or less climax tendencies, and all but 
one or two of them are common above the fall-line, so it is not 
surprising that they are less frequent coastward. Most of the 
latter, on the other hand, are confined to the coastal plain, or 
nearly so. Alnus rugosa, common in the Cretaceous, was not 
noticed in the Eocene region at all, while the reverse is true of 
Pinus glabra, Magnoha grandiflora, and Acuan illinoense. 
Considering the table as a whole again, it is noteworthy that 
most of the species seem to have their greatest development 
(or centers of distribution) in the Mississippi Valley,* and that 
most of the monocotyledonous and many of the dicotyledonous 
genera have tropical representatives. The families most largely 
represented in the table are Compositae, Euphorbiaceae, Legum- 
inosae, Cupuliferae, Cyperaceae, and Gramineae. Such large fam- 
ilies as Solanaceae, Labiatae, Gentianaceae, Ericaceae, Umbel- 
liferae, Hypericaceae, Rosaceae, Cruciferae, Caryophyllaceae, 
Ranunculaceae, Orchidaceae, Liliaceae, and Juncaceae, and such 
genera as Viola, Carex, Rynchospora, Scirpus, and Panicum, which 
are well represented in other parts of Alabama, are scarce or ab- 
sent on the river banks. About 20 per cent. of the angiosperms 
are monocotyledons, but perhaps the number of species involved 
is too small for this fact to be of much significance. 
The weeds + along the river furnish an interesting problem. I 
was surprised to find them so numerous in spots so remote from 
human habitations and so rarely trod by the foot of man. They 
are common on all the bluffs, and as many of them are known to 
have been introduced from foreign countries in comparatively re- 
cent times, the vegetation of some parts of the river-banks must 
present quite a different appearance now from wit it a a cen- 
* See Ann. N. Y. wes Sci. 17: 74. 1906; Torreya 7: 44. 1907- 
+ By ‘‘weed”’ is here meant a species which grows chiefly in unnatural habitats 
created by civilization. See Bull. Torrey Club 35: 347- 190 
