A, W. JEvans — North American Species of Fridlania. 7 



Dioicous. 



Lobes not cordate at base ; leaf-cells in middle of lobe with incon- 

 spicnous trigones and no intermediate thickenings ; branches 

 often terminating in upright, leafless flagella with squarrose 

 underleaves. 3, F. Bolanderi. 



Lobes cordate or auricnlate at base ; leaf -cells in middle of lobe 

 with conspicuous trigones and occasional or frequent interme- 

 diate thickenings ; branches not terminating in leafless flagella. 

 Leaves strongly squarrose when moist. 7. F. squarrosa. 



Leaves scarcely or not at all squarrose when moist. 



Lobule usually explanate. 6. F, riparia. 



Lobule usually inflated. 



Lobule inflated in upper and outer pai'ts, compressed 

 below ; underleaves dentate or crenate on the sides 

 above the middle ; perianth strongly tuberculate with 

 more or less distinct supplementai-y ridges. 



8. F. BrittonicB. 



Lobule inflated throughout, underleaves entire or uniden- 

 tate on the sides. 

 Perianth with one or more distinct roughened supple- 

 mentary ridges both antically and postically. 



9. F. Virginica. 



Perianth smooth and without distinct supplementary 

 ridges. 10. F. Fboracensis. 



2. FruUania Oakesiana Aust., Proc. Acad. Phila. for 1869: 226. 



Plate I. figs. 7-15. 

 Autoicous : plants closely appressed to matrix, reddish-brown, vary- 

 ing to greenish: stems irregularly pinnate; leaves imbricated, the 

 lobe orbicular to ovate, slightly squarrose, arching over the stem but 

 not cordate at base, slightly decurved at the rounded apex, entire or 

 nearly so ; lobule large, galeate, truncate at base, close to the stem ; 

 stylus minute : underleaves distant or subimbricated, plane, obovate 

 or rhombic, bifid about one-third with acute lobes and narrow sinus, 

 margin entire or unidentate on one or both sides : leaf-cells in middle 

 of lobe with rather thick walls and inconspicuous trigones but with- 

 out intermediate thickenings : $ inflorescence terminal on the stem 

 or a main branch ; bracts in about two pairs deeply and unequally 

 bifid, the lobe ovate, rounded at the apex, entire, lobule about as long 

 as the lobe but narrower, ovate, obtuse or acute, entire but bearing a 



