1896, ] Flora of Chicago and Vicinity. 121 
quent in some sections about Chicago, that it is hardly recog- 
nized as of the same species. The pointed leaves are usually 
narrower than in the arboreous hackberry, from narrow 
ovate to ovate-lanceolate, many of them falcate. Occasion- 
ally they are broad and short, both forms occurring on the 
indiameter. When ripe it is of a dark brownish purple color. 
The flesh is orange colored as well as the stone and seed. 
There are some features in which it resembles C. Misstsstp- 
piensts Bosc, as in the size of the fruit. This variety of the 
hackberry isa south Atlantic species, ranging westward, ac- 
cording to Sargent’s Silva of North America 7: 69, to Missouri, 
Colorado, Utah and Nevada, and growing on the rocky banks 
of streams. Here it occurs in the sand of the dune region, 
neat the shores of the lake. I have traced it for a distance 
of three miles. 
ALNUS GLUTINOSA Willd.—This is used in some parts of 
the city as a shade tree, and has become naturalized in some 
places south of Jackson Park. It has spread into the wet land, 
Making thickets of low trees and bushes like the common al- 
Gora. They fruit when at the height of four to six feet. 
POTAMOGETON DIVERSIFOLIUS Raf. (P. hybridus Michx). 
~The point nearest the city where I have seen this is La- 
-, Where plants grow in shallow pools by the bord- 
ne Lake. 
thie 'NTERRUPTUS Kitaibel. Two localities are given for 
* Pondweed in Morong’s Naiadacee of North America: 
Mien found in the Calumet river at South Chicago. In Hig- 
din’s Flora of Cook county, Ill., and a part of 
a 
me county, Ind.,® this is mentioned as a broad leaved form 
7 
M 
wee ot Bot Club. $a ihr 
‘Baie 262. 1881 
Of Chicago Acad. of Sci., 2: 124, 1891. 
