692 MINNESOTA BOTANICAL STUDIES. 



much smaller, the basal auricles less excavate, the costa faint, 

 not extended into the obtuse apex. Antheridial buds numer- 

 ous along the middle part of the stem, shorter than the leaves, 

 in their axils, with few paraphyses, and perichaetial bracts 

 ecostate. Fruiting plants were not found. 



This plant is near Hypnum cordifolium, but differs from this 

 species in having its leaves much more closely set on the stem, 

 costate to apex, and much ivider in proportion to length; also in 

 having the larger cells of the auricles abruptly enlarged, and 

 the leaf cells proper smaller. 



It is also near Hypnum giganteum, but differs from it by its 

 unusually broad leaves, its smaller size, dark green color, and 

 fewer branches shorter. 



M. Cardot has kindly compared it with the type of Hypnum 

 orbicularecordatum R. & C, and pronounces it a distinct and 

 new species. 



Dr. Best has also examined the plant with care, and has 

 aided me by kindly sending, for comparison, specimens of 

 Macoun's Hypnum giganteum, of typical H. cordifolium, and 

 of his own H. cordifolium var. ramosum MS. I cannot, at this 

 time, enter into a detailed criticism of these species and how 

 variously they seem to be understood by different students. I 

 only wish to state, in closing, that, as a result of my study of 

 the number of specimens of Caliergon of North America to 

 which I have had access, I concluded that it would be best to 

 publish the plant under consideration provisionally as a species, 

 rather than as a variety of one of the established species. 



There is at hand an abundance of material of this plant, 

 which will be distributed shortly in my third fascicle, Nos. 

 101-150, of Mosses of Minnesota, so that all interested may 

 study it. 



Plate XXXIX. 



Hypnum cyclophyllotum, Section Caliergon. 



Figs. 1, 2, 3. Plants, natural size. 



Fig. 4. Piece of stem, enlarged, to show phyllotaxy. 



5. Stem leaf, x 56. 



" 6. Branch leaf, x 56. 



'• 7. Lower part of stem leaf, x 56. . 



" 8. Antheridial bud, opened, x 56. 



" 9. Cross section of leaf, x 96. 



" 10. Leaf of Hypnum cordifolium, x 22. 



