MEMOIRS OF 



THE NEW YORK HOTAXICAL OARDEX 



[VOL. 11 



Teeth of the leaves well developed. 



Uuderleaves small, rounded, distant; leaf apices broad, trans- 

 versely truncate; trigones conspicuous 21. B. tricuspidata. 

 Uuderleaves approximate to imbricate, broader than the stem. 

 Leaf cells mostly 30-36 the trigones very large, knot-like ; 

 leaves spreading to falcate, the teeth often coarse, sharp; 

 plants yellow-brown to reddish-brown. 25. B. longa. 

 Leaf cells mostly less than 28 n. 



Underleaves squarrose-spreading, never hyaline; plants olive 

 to brownish or becoming reddish; leaves spreading to 

 ascendent or recurved; cells 20-26 X 22/z. 



23. B. tricrenata. 



Underleaves not squarrose. 

 Leaves spreading or rarely ascendent; cells 16-20 X 18 M, 

 the walls thin, the trigones inconspicuous; underleaves 

 often hyaline on the margins; plants green to green- 

 ish-brown. 12. B. taleana. 

 Leaves ascendent, obliquely truncate ; cells mostly 24 n 

 (rarely to 30 fi), the trigones small but conspicuous. 



22. B. longistipula. 

 Underleaves longer than broad, rectangular in outline, the bases not 

 cordate. 



Leaves ascendent, obliquely truncate; cells 24 n (rarely to 30 /i), the 

 trigones small, conspicuous ; plants green to yellow-brown. 



22. B. longistipula. 



Leaves spreading, sometimes falcate. 



Underleaves entire, usually faintly lobed at the apex. 



Leaves spreading, long, the teeth of medium size; leaf cells mostly 



24 fi, the trigones small but conspicuous. 24. B. latidens. 



Leaves spreading to falcate, the teeth often coarse, often ending 

 in a spine; leaf cells 30-36 with very large trigones. 



25. B. longa. 



Underleaves with a few spines, teeth, or lobes on the apical margin. 



Underleaves deeply 4-lobed. 27. B. elongata. 



Underleaves not deeply 4-lobed. 



Plants green becoming brownish ; leaf cells mostly 30-36 



with large knot-like trigones. 8. B. pallide-virens. 



Plants deep brown becoming blackish ; leaf cells mostly 40-45 /i, 

 the walls very thick from coalesced trigones. 



28. B. crassidentata. 

 Underleaves oval to reniform, rounded to cordate or auriculate at the 

 base. 



Underleaves reniform, cordate to auriculate at the base. 



Underleaves inflated, the yellow-brown margins appressed to the 



stem ; leaf cells mostly 18-22 n. 29. B. jamaicensis. 



Underleaves plane, the margins rarely pigmented; cells of the apical 

 part elongated and with knot-like intermediate thickenings 

 on the walls ; leaf cells mostly 24 n or more in diameter. 



30. B. wrightii. 



Underleaves oval, the base rounded to cordate. 



Apical margin of the underleaves retuse, the lateral margins 



recurved. 19. B. acuminata. 



Apical margin of the underleaves entire or sinuate but not retuse. 

 Leaves strongly arcuate, the ventral margin deeply concave from 



a large rectangular ventral auricle. 31. B. arcuata. 



Leaves spreading to arcuate but not as above. 



Cells of the apical part of the underleaves elongate and with 

 intermediate thickenings on the walls; leaf cells mostly 

 24/t or more. 30. B. wrightii. 



Cells of the apical part of the underleaf quadrate (the walls 

 often somewhat thickened and pigmented) ; leaf cells 

 mostly 18-22 ft. 29. B. jamiaicensis. 



