214 THE AMERICAN NATURALIST. 
stipules, in which it is shown that the protective scales of winter 
buds may be either pedestals of last year’s leaves, modified bases of 
leaves, leaf blades, modified leaves, stipules, connate pairs of stipules 
belonging to the same leaf, or connate pairs of stipules belonging to 
different leaves. 3 
In the issue of Science of Dec. 17, 1897, Dr. J. W. Harshberger 
published an article on “The Native Dahlias of Mexico,” in which, 
especially, the conditions under which these popular garden plants 
naturally occur and their natural color variation are made the sub- 
ject of inquiry. : 
The mucilage cells of Opuntia have been made the subject of 
a recent study by Longo,’ who states that they occur distributed 
through the fundamental parenchyma of all members of the plant, 
that their mucilage does not result from a transformation of the 
cell wall, but is a direct product of their protoplasm, and that their 
function is that of a water tissue. The same author has also? 
studied certain crystal and mucilage cells which are found in the 
branches and fruit of Platopuntias, though absent from the Cylindro- 
puntias. 
To students of the African flora the series of papers on Italian 
collections of Harar and Somali plants being published by the staff 
of the Berlin Garden in current numbers of the Aznuario of the 
Botanical Institute of Rome should be of interest. A number of 
new species are described. 
1 Annuario del R. Ist. Bot. di Roma, 7: pp. 44-57, pl. 2. 
2 Loc. cit., pp. 79-83, pl. 8. 
