1886, ] Botany. 887 
upon one or both surfaces of most grass and sedge leaves. Their 
office appears to be to roll up the leaves when evaporation becomes 
excessive, and thus reduce the amount of exposed surface. The 
orm and position of the cells is usually characteristic of each 
Species, as was well illustrated by the paper. Charts showing 
enlarged sections of each leaf enabled the listener to intelligently 
follow the descriptions. 
2. Synopsis of North American pines based on leaf anatomy. By J. M. Coulter. 
The author has made a careful and critical study of the value 
of the histological character of leaves in determining the rela- 
tionships of the members of this group of plants, and finds them 
of more service than heretofore recognized. Those especially to 
be relied upon are the resin ducts, the fibro-vascular bundles and 
the hypodermal tissues. The value of each is pointed out, and a 
eion of species given to accord with the results of the 
study. 
3. es pevelopmrentt of the Gymnosporangia of the United States. By W., G. 
arlow, 
The Paper embodied the results of numerous cultures carried 
on in connection with work at the Harvard ryptogamic labora- 
tory. The spores of the Gymnosporangia were sown upon the 
leaves of several species of fruit trees, and more satisfactory 
Certainty several species of this genus with as many species of 
Reestelia. The investigation has given rise to some troublesome 
Problems which are left for future study. 
4. Plan for laboratory work in chemical botany. By Lillie J. Martin. 
Miss Martin does excellent service to botany in this country 
by calling attention to the advantages in studying the chemical 
Constitution of plants as a department of botany. Her paper is 
Particularly devoted to a consideration of the requirements of the 
Student in taking up the subject, even to the matter of desk con- 
veniences, 
5. Memoranda of a revision of the North American violets. By Asa Gray. 
he paper gives the results of a recent study of all available 
Material, bringing this genus into much more satisfactory sha 
6. A picvision of the North American species of the genus Fissidens. By C. R. 
es, 
The author has applied the same critical judgment to this 
Sroup of mosses that has prevailed among our best systematists 
When treating of the flowering plants, and the result is undoubt- 
edly of corresponding value. The most important change is the 
sorption of the genus Conomitrium. 
_ besides the above a number of papers presented to the asso- 
ciation were more or less botanical. A brief reference to them 
Will be sufficient for the present connection. 
