Monograph of the Leraaneaceae of the 
United States. 
BY 
Geo. F. ATKINSON, 
Professor of Biology , Alabama Polytechnic Institute, Auburn, Alabama, U.S.A. 
With Plates VII, VIII and IX. 
Introductory 1 . 
HE investigations leading to the present Monograph of 
A the Lemaneaceae of the United States were undertaken 
at the close of the month of December, 1884, and concluded 
in November, 1889. The research has been prolonged 
through nearly five years in order to repeat the work, both 
for the purpose of verifying the observations and to eliminate 
so far as possible any items of error. 
The obscurity of some of the phases in the life-history 
of these plants ; the difficulties attending the collection of 
material owing to their peculiar habitat and the rigors of 
winter during which time they pass through the greater part 
of their development ; have deterred me from presenting the 
work for publication before at least the complete life-history 
and anatomy of the two natural groups to be found in the 
genus should have been examined in detail. 
Sirodot 2 discovered the organs of reproduction and certain 
structural characters naturally differentiating the species of 
Lemaneaceae into two well - defined groups. These he 
1 The works referred to are enumerated in the Bibliography on p. 212. 
F 2 fitude sur les Algues d’eau douce de la Famille Lemaneacees, Ann. d. Sci. 
Nat. 5th Ser. Bot. xvi, 1872. 
[Annals of Botany, Vol. IV. No. XIV. May 1890.] 
N 
