16 A. W. Evans — North American Species of Frullania. 



or obtuse (sometimes apiculate), entire or slightly crenulate, lobule 

 shorter and narrower, ovate or lanceolate, subacute or apiculate, 

 bearing a small tooth or stylus at or below the middle of the inner 

 edge, otherwise entire ; bracteole free or slightly connate on one 

 side with bract, ovate, bifid one fourth or more with acute lobes and 

 sinus, entire or unidentate on one or both sides ; perianth emersed, 

 obovate, truncate above and abruptly narrowed into a long, slender 

 beak, compressed at the sides and with abroad postical keel and one or 

 more short, supplementary antical and postical ridges, the whole 

 surface being provided with scattered tubercles especially numerous 

 on keels and ridges : $ bracts in many pairs, occupying a short 

 lateral branch and forming an oblong spike. 



Stems 0-18'"°' in diameter; lobes of leaves 0-60™°' long, 0-75'"°^ 

 wide, lobules 0-25™"" long and wide; underleaves 0-30'^'^ long, 0-3'7°'" 

 wide; leaf-cells from edge of lobe 0-014"^™, from middle 0-022™"^ in 

 diameter and from base 0-032'^'" long, 0-025°^'^ wide; bract I, lobe 

 1-35'"'^ long, 0-75"'° wide, lobule roO'^"' long, 0-50"°' wide ; bracteole 

 I, 0-85'^°' long, O-SO"^'" wide ; bract II, lobe l-OS'""^ long, 0-65'"'" wide, 

 lobule 0-7 S'"'" long, 0-65'"'" wide; bracteole II, O'lO^"^ long, 0-35'"'^ 

 wide ; perianth 1-90'"'" long, 1-20™'° wide. 



On rocks and ti'ees ; Central New York (Underwood) : Holston 

 River and Slemp's Creek, Virginia (Mrs. B|§tton and Miss Vail) : 

 Meriden, Connecticut (Evans): Canton, Illinois (Wolf): Easton,. 

 Pennsylvania (James). Distributed in Hep. Amer, 7i. Jf.8 (as JB. 

 dilatata); in some sets there is admixture with ^. Eboracensis. 



In a sterile condition the present plant strikingly resembles the 

 European F. dilatata, and it is little wonder that they have been 

 considered the same. The involucre and perianth, however, afford 

 safe points of distinction : in F. dilatata the lobes of the bracts are 

 broader than in our plant, the innermost bracteole is bifid with its 

 lobes deeply cut into two or three segments, and the perianth is sim- 

 ply trigonous and narrowed into a short, broad beak. The long, 

 slender beak of the perianth is indeed a most peculiar feature of F. 

 BrittonicB and serves, together with the numerous tubercles, to dis- 

 tinguish the species from all other North American Frullanioe, But, 

 even in the absence of inflorescence, there is little danger of mistak- 

 ing the present species, for the points which ally it with F. dilatata 

 separate it from other TrachecolecB, viz., the larger size of the plant, 

 the curious inflation of the lobule and the broad underleaves with 

 their peculiar dentation. I take pleasure in naming this distinct and 

 beautiful species in honor of Mrs. Elizabeth G. Britton, whose care- 

 ful work on American mosses is so highly appreciated by bryologists. 



