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1897} NORTH AMERICAN SPECIES OF AMBLYSTEGIUM 243 
may have is due to the kind cooperation of friendly bryologists. 
I gladly acknowledge the assistance thus received from many 
sources, without which my study would have been impossible, 
and here express my sense of indebtedness and my thanks for 
this assistance. Professor Charles R. Barnes of the University 
of Wisconsin, by giving to me at all times without stint his 
kindly interest and help in manifold ways, as well as by command- 
ing for my use all the facilities in the power of the University 
for carrying on my work," has placed me under the greatest ob- 
ligations. To Mrs. Elizabeth G. Britton of New York, for the 
use of Amblystegium material in the Columbia University Her- 
barium, which she placed entirely at my command, and for many 
other favors; to Professor John Macoun of Ottawa, Ontario, for 
specimens of several forms not elsewhere available; to Professor 
John M. Holzinger, of Winona, Minnesota, for the use of type 
and other specimens; to M. Jules Cardot, of Stenay, France, for 
material; to Dr. B. L. Robinson, of Harvard University, for type 
specimens; and to Mr. Frederick V. Coville, of Washington, D 
C., for books loaned, I offer my sincerest thanks. 
AMBLYSTEGIUM Br. & Sch. 
Amblystegium Bry. Eur. Monog. Amblystegium. 1853. 
Hypnum pp. plur. auct. 
Leskea pp. plur. auct. 
Gametophyte bisexual rarely unisexual, varying in size from 
very minute to very large and robust; bright green, dark dull 
green, yellowish green to yellow or sometimes bronze ; prostrate, 
creeping, decumbent, ascending or erect: stems for the most 
part slender, soft, occasionally rigid; abundantly and commonly 
irregularly branched, rarely subpinnate ; with or without central 
Strand ; sometimes obscurely angled; branches flexuous, ascend- 
ing or erect: leaves five to eight-ranked, generally spreading 
*Among the type material which I have consulted none was more useful than 
Specimens from the herbarium of Palisot de Beauvois. All his American types have 
been sent to the University of Wisconsin for examination through the courtesy of Dr. 
J. Briquet, curator of the Delessert Herbarium of Geneva, Switzerland. These types 
will all be studied and illustrated by figures in the course of a few months. 
