14 A. W. Eoans — JVbrth American Species of Frullmiia. 



known, and Professor Massalongo' suggests that the two species may 

 be identical. The Italian plant shows the same general appearance 

 as oiu's, the same characters in lobes, underleaves and areolation, and 

 the same great variability in the lobules, but it shows also slight 

 differences in bracts and bracteoles. It seems safest, therefore, to 

 keep the plants apart until both are better known. F. riparia is 

 most readily distinguished from its American allies by its lobules, 

 which are rarely inflated but usually wholly or partially explanate. 

 Of course a character of this sort is not very satisfactory, as sev- 

 eral other species may show a similar variability in the shape of the 

 lobule if growing in sheltered places. F. riparia also differs from 

 F. squarrosa in its looser Jiabit, less squarrose and narrower lobes and 

 in its free bracteoles ; from F, Yirginica and F. Fboracensis, in its 

 larger size, ovate lobes, and broader underleaves. 



7. Frullania squarrosa (Bl, R. et Nees) Dumort., Recueil d' Obs. sur les Jung., 

 13. 1835. 



Jungermannia squarrosa Bl. R. et Nees, Nova Acta Acad. Caes. Leop., xii: 219. 

 1824. 



Plate VI. 



Dioicous : plants closely appressed to matrix or more commonly 

 growing in loose, wide mats, green, varying to reddish-brown : stems 

 irregularly pinnate : leaves densely imbricatecJ, the lobe rolled about 

 the stem when dry, strongly squaiTOse when moist, very fragile in 

 texture, broadly ovate, arching over the stem and cordate or auricu- 

 late at base, rounded at the apex, entire ; lobule galeate, inflated, 

 especially in upper and outer parts, compressed at base, sepai'ated 

 from the stem by about one-fourth its width ; stylus minute : under- 

 leaves subimbricated, orbicular, plane or nearly so, entire or spar- 

 ingly repand-dentate : leaf-cells from middle of lobe rather thick- 

 walled with distinct trigones and intermediate thickenings : $ in- 

 florescence terminal on a short lateral branch ; bracts in about three 

 pairs, unequally bifid, the lobe ovate to orbicular ovate, rounded at 

 the apex, entire ; lobule ovate or broadly lanceolate, acute, bearing 

 one or more small subulate teeth near the base on the inner edge, 

 otherwise entire ; bracteole connate on one or both sides with bracts, 

 approximately orbicular, deeply bifid to the middle or beyond with 

 acute lobes and sinus, entire or slightly toothed or lobed toward the 

 base, often revolute on the borders : perianth oblong, compressed, 

 narrowed into a short bi'oad beak, strongly unicarinate postically 



1 Atti del Congr. Nazionale di Bot. Crittog. in Parma, 10 (sep.) 1887. 



