THE BRYOLOGIST 



Vol. III. July, 1900. No. 3. 



FISSIDENS IN NORTHEASTERN NORTH AMERICA. 



By Ann'e Morrill Smith. 



IT is very easy to recognize a Fissidensif looked at carefully with 

 a hand lens, and under the microscope with even a very low 

 power one need not hesitate. The leaves are entirely different 

 from any of the mosses already studied in The Bryologist. They 

 are in two ranks and apparently edgewise to the stem, with 

 the basal portion of the upper edge apparently split in two and 

 sheathing the stem and the lower edge of the leaf next above it. as 

 shown in the figure. In Bryum the border is made up of cells of 

 an entirely different character and shape from those of the rest of 

 the leaf, while in Fissidens the border cells are of the same size 

 anddifferonly in being of a lighter color, or paler, as the key says. 

 The leaf then consists of three parts, differently named by different 

 authors. I prefer to follow in this study Prof. Charles R. Barnes' 

 Revision of the North American Species of Fissidens, Botanical 

 Gazette, Vol. XII. J inuary and February, 1887. The three parts 

 are called 7'aginant lamina, vertical lamina and inferior lamina 

 to designate respectively the sheathing or conduplicate portion of 

 the leaf, Fig. 3, a ; the whole of the vertical blade, b ; and the 

 part of it below the costa, c. The peristome is so much like that 

 of the Dicranums that the families to which these genera belong 

 are usually regarded as somewhat closely allied. 



For the benefit of the more advanced students I refer them 

 to a reprint on "The Genus Fissidens." by Ernest Stanley 

 Salmon, of Charlton House. Kew, England, \n Annals of Botany, 

 Vol. XIII. March, iSgq. This, in three double plates, gives 94 

 figures and is very full regarding the morphology of the genus as 

 well as classification. 



Key to the species;* 



A. — fruit terminal. 

 Leaves with a narrow border, at least on the vaginant lamina — 



Border usually confluent at apex with percurrent costa; 



male flowers axillary F. brvoides. 



Border wanting at apex; male flowers at base of stems; 

 leaf cells smooth F. tncurvus. 



Border none except on vaginant lamina; leaf cells papil- 

 lose F. Ravenelit, 



*I am greatly indebted to Prof. Charles R. Barnes for invaluable 

 assistance in preparing this key. 



