—25— 



by the characters given in the key. D. Drtimmondii grows in 

 much the same situations as the wavy Dicranum, and is frequently 

 mingled with it. Its capsules are also clustered and the leaves 

 slightly wavy. The waviness of the leaves is much less marked 

 and the plants have not the same silky sheen. The upper leaf 

 cells are much shorter, nearly as broad as long and afford a sure 

 ground for distinction. D. viride is probably not very rare, but 

 is almost always sterile. It can be distinguished by the broken- 

 leaf apices and the other characters given in the key. D. spurium 

 does not look like a Dicranum because of the equally spreading 

 soft crisped-incurved leaves. Under the microscope its leaves are 

 readily distinguished from those of any other species by the large 

 and conspicuous papillae which cover the upper part of the back 

 of the leaf and are easily seen because the margins are incurved 

 in this region. Dicranella heteromalla has the same general ap- 

 pearance as the Dicranums, and is very common. It is smaller than 

 most of the Dicranums, and its leaves lack the inflated angular 

 cells so characteristic of Dicranum. Other species of this and 

 allied genera may be met with, but they can readily be distin- 

 guished from Dicranum by the characters mentioned in the last 

 article. 



GEOGRAPHICAL DISTRIBUTION OF DICRANA. 



By Rodney H. True. 



AT the suggestion of Dr. Grout, I have prepared the follow- 

 ing brief statement of the distribution of twenty species 

 of the genus Dicranum selected by him. I have used such 

 local lists and similar helps as were at my disposal and wish it 

 borne in mind that I am not able to warrant the accuracy of the 

 determinations on which they were founded. I hope, however, 

 that, by reference to a large body of authentic herbarium ma- 

 terial, I have been able to give a substantially correct idea of the 

 distribution of these mosses. I should be willing, as far as my 

 time permits, to determine doubtful forms for any who care to 

 send specimens and letter postage for reply. 



Dicranum Bergeri Bland. A moss characteristically found 

 in marshy places, most frequently in sphagnum bogs; widely dis- 

 tributed.— N. J., New Erg., Can., Greenland, Wis., Minn., Rocky 

 Mts., Alaska. 



Dicranum Blytii Schimp. (D. sckzsti). A rare Arctic 

 species.— White Mts., Labrador, Greenland, Selkirk Mts., Van- 

 couver Id., Brit. Col. 



