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



leaves distant, reniform, cordate at base, bifid about one-fourth, with 

 obtuse or subacute lobes and sinus : leaf-cells of lobe rather thick- 

 walled with conspicuous trigones and intermediate thickenings : 

 $ inflorescence terminal on a short, simple, lateral branch ; bracts in 

 about three pairs, unequally bifid, the lobe ovate, rounded at the 

 apex, irregularly crenulate, lobule shorter and narrower, ovate, 

 rounded at apex, irregularly crenulate and bearing at or below the 

 middle of the inner edge a tooth-like, often laciniate segment or 

 stylus ; bracteole free from bracts, ovate, deeply bifid with subacute 

 lobes and sinus, the lobes variously laciniate, dentate or crenulate ; 

 perianth about half exserted, oblong or obovate, narrowed into a 

 short, broad beak, compressed on the sides, with a broad postical 

 keel and a shallow antical sulcus, smooth : $, spike terminal on a 

 short lateral branch, globose, bracts in two or three pairs. 



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

 wide, lobules 0-18™"' long and wide; underleaves 30™°i long, 0-40™'^ 

 wide ; leaf -cells from edge of lobe 0-()14™™, from middle 0-019'°™ and 

 from base 0-028'^'^ in diameter; bract I, lobe l-OO""^ long, O-Go™"^ 

 wide, lobule O-BO""^ long, 0-35™" wide ; bracteole I, 0-65°^°^ long, 

 0.4omin ^j(jg . i3j.act II, lobe 0-80'"'" long, 0-60™'" wide, lobule 0-45'"'^ 

 long, 0-30"™ wide ; bracteole II, 0-50™™ long, 0-40"''" wide ; perianth 

 1-90™°^ long, 0-90™'" wide. 



On shaded rocks: French Broad River, Tennessee (Sullivant) ; 

 Closter, New Jersey (Austia) ; Sand Lake, New York (Peck) ; 

 Woodbridge, Connecticut (Evans). Distributed in Muse. Alleg. 

 n. 269 (as F. dilatata, var. 3) and in Hep. Bor.-Amer. n. 102. 



Frullania plana is by no means a typical Homotropantlia but it 

 shows its relationships with this group rather than with Trachycolea 

 by the union of the following characters : - (1) the broad, cordate 

 underleaves, (2) the autoicous inflorescence, (3) the female flowers 

 borne on simple lateral branches, and (4) the smooth trigonous 

 perianth. The lobule, however, although small for the size of the 

 plant, is never reflexed, as in F replicata^ etc. The present plant is 

 usually sterile, but its peculiar underleaves will serve to distinguish 

 it even in this condition. 



Subgenus IV.— THIOPSIELLA Spruce. 



Key to the Species. 



Underleaves reflexed, at least toward the apex. 



Lobes acuminate or acute ; underleaves not crispate at base ; 

 bracts subentire ; innermost bracteole connate on both sides. 



12. JF. Ntsquallensis. 



