PLATE X. 



1. Hypnum squarrosum (a procumbent form) 



a. leaf from behind, magnified. 



b. sporangium, magnified. 



2. H. aduncum. 



a. leaves, magnified. 



b. sporangium, magnified. 



3. H. fluitans. 



a. leaves, magnified. 



b. sporangium, magnified. 



4. H. revolveiis. 



a. leaves, magnified. 



b. sporangium, magnified. 



5. H. commutatum. 



a. leaf from behind, magnified. 



b. sporangium, magnified. 



6. H. filicinum. 



a. leaves, magnified. 



b. sporangium, magnified. 



