1915] CURRENT LITERATURE 259 
light intensity decreased the thallus decreased in size, the air chambers de- 
creased in number per unit area, and chloroplasts appeared in the dorsal 
epidermal cells. In the region of least light intensity and in dripping water 
a form was found which showed neither air chambers, ventral scales, nor 
tuberculate rhizoids. Miss MAysrooxk concludes that the factors responsible 
for this condition of the thallus are diminished light intensity and excessive 
moisture. Since none of these plants were in fruit the question of identity 
naturally is of prime importance. The long series of recently conducted 
experiments on undoubted Fegatella conica by BRYAN in this laboratory show 
that under extreme conditions of moisture the air chambers can be somewhat 
modified. Bryan eliminated neither air chambers nor ventral scales. The 
teviewer considers the presence of air chambers and ventral scales of such 
importance in undoubted Marchantiales that he hopes Miss Maysroox will 
place some of the plants under suitable conditions for fruiting in order that 
there may be no doubt of their identity.—W. J. G. LANp. 
Notes from Florida.—HARSHBERGER’ has written a popular sketch of 
his journey across the Everglades, promising later to give a detailed account 
of the plant formations studied. Attention is called to the great lack of scien- 
tific knowledge of this region. South Florida is regarded as that portion of the 
State south of 27°. Brief treatment is given the plant and animal life, agri- 
cultural possibilities, and other topics. 
ESSEY® has given a brief description of the hammocks, as they are seen 
about Miami, contrasting them with the pine lands and with the Everglades. 
Reference is made to a number of the more interesting species, and the cause 
of the sharp contrast between the vegetation of the pine lands and that of the 
Aeon is discussed. 
In a steamboat ride up the Apalachicola River, R. M. Harper? noted a 
einadickbie change in the bank vegetation in the progress of the journey. 
ong the possible explanations suggested for this common phenomenon, the 
chief place is given to the probability that the upstream plants require or 
tolerate greater fluctuation in level than do the plants of the estuarine swamps, 
in which, of course, the seasonal changes in level are small.—H. C. CowLEs 
An ecological study of weeds.—Weeds have been largely neglected by 
ecologists and phytogeographers, who for the most part have concerned them- 
selves with the more primeval types of vegetation. For several years Miss 
RENCHLEY has been making observations on the soil relations of weeds, and 
7HARSHBERGER, J. W., South Florida; a geographic reconnaissance. Bull. 
ie ae Phila. 10:37-47. ps 10. 1912 
, E. A., The hammocks and a coeties of southern Florida. Plant 
World biscback bn. 2. IQII. 
* Harper, R. M., The river-bank vegetation of the lower Apalachicola, and a 
new principle illustrated thereby. Torreya 11:225-234. fig. I. 1911. 
