385 



Leaves not specially nanowed above the base. 



Perianth linear-fusiform, widest below the middle; dioi- 

 cous. 4- C. catentilata. 



Perianth linear-clavate, widest above the middle ; dioicous 

 orautoicous. 5- C. Virginiana. 



Leaves medium size, 0.5-0.65 mm. long; leaf-cells 40-50 ,«. 



Leaves longer than broad, cleft half way to the base or more ; per- 

 ianth thin. 



Smaller; leaves 0.5 mm. or less long; usually monoicous. 



6. C. bicuspiJata, 

 ■ Larger; leaves 0.65 long with apiculate divisions ; dioicous. 



7. C. extensa. 

 Leaves as broad or broader than long ; monoicous ; perianth fleshy, 



usually narrowed at base. 8. C. pleniceps. 



Leaves larger, 1-1.35 mm. long, usually narrowed at base; plant semi- 

 aquatic. 9. C.fluitans. 

 Leaves only about the width of the stem or even narrower; innermost 

 involucral leaves united into a cup. § Cephaloziella. 

 Plants small ; stems 2-4 mm. long. 



Perianth linear or narrowly fusiform, the mouth denticulate or 



nearly entire. JO. C divaricata. 



Perianth ovate-fusiform, the mouth ciliate. 11. C. Macounii. 



Plants minute ; stems less than 2 mm. long. 



Underleaves lanceolate, entire, often present only near the end of 

 the stem. 12. C Sullivantii. 



Underleaves everywhere present, the upper ones bifid. 



13. C. mini in a. 

 Branching lateral ; leaves bifid with dentate margins; perianth terminal ; under- 

 leaves usually present. § Prionolobus. 

 Leaves complicate-bifid, equitant. 14. C Turneri. 



I. Cephalozia CURVIFOLIA (Dicks.) Dumort. Recueil d' Obs. sur 



les Jung. 18. 1835. 



Jungcrmminia airvifolia Dicks. PL Crypt. Brit. 2 : 15. //• J,/ 

 7. 1790. 



Noiuellia cwvifolia Mitt, in Godman, Nat. His. Acores, 321. 



1870. 



Gametophyte a green or reddish slender creeping leafy axis, 

 sparingly branching; leaves somewhat orbicular, deeply concave, 

 with two slender incurved teeth widely separated at base and soon 

 becoming one cell wide; underleaves wanting; leaf cells isodia- 

 metric, 20-25 // in diameter: monoicous or dioicous ; perianth on 

 a short branch, triangular-prismatic, about 1.3 mm. long, plicate, 

 with the mouth constricted and short ciliate; involucral leaves in 

 two or three ro.v.s, deeply bifid with broad serrulate divisions. 



