JUNGERMANNIACK.K. (SCALE-MOSSES.) 717 



20. PLAGIOCHILA, Dumort. (11.24.) 



Leaves large, succuhous, rounded or truncate above, dentate or spinose or 

 rarely entire, the dor.sal margin retlexed ; undcrleaves usually none. Dia-cious 

 or monrecious. Fruit terminal, or axillary by tlie growtb (»f offshoots. Invo- 

 lucral leaves larger than the cauline; perianth laterally comjiressed, erect or 

 decurved, oblicjuely truncate and bilabiate, the b^bes entire or ciliate-dentatc. 

 Capsule thick, oval. Elaters attached to the middle of the valves. Autheridia 

 oval, 2 - 3 in the axils of spicate leaves. ( Name from vKdyios, oUique, and x^^^o^, 

 Up, from the form of the perianth.) 



# Umhrleaces 2 -3-rlrft, fugacious. 



1. P. porelloides, Lindeub. Branches ascending; leaves suljimbricate, 

 convex-gibbous, round-obovate, the u])perniost repand-denticulate, the rest en- 

 tire, tlic dorsal margin reflexed; jierianth terminal, oblong-ovate, the mouth 

 compressed, denticulate. — Among mosses in swamps and river-bottoms; 

 common. 



2. P. interrupta, Dumort. (PI. 24.) Prostrate, horizontally branched, 

 copiously rooting ; leaves imbricate, horizontal, oval, entire or slightly repand ; 

 underleaves lanceolate ; perianth terminal, broadly obcouic, the mouth com- 

 pressed, repand-crenulate. (P. macrostoma, SuHiv.) — Moist banks and de- 

 cayed logs, N. Eng., Ohio, and northward. (Eu.) 



* * Underleaves wanting. 



3. P. spinul6sa, Dumort. Creeping, branches ascendiug; leaves re- 

 mote, obliquely spreading, obovate-cuueate, the dorsal margin retlexed, entire, 

 the ventral and apex spinulose-toothed ; perianth rounded, at length oblong, 

 the mouth spinulose. — Shaded rocks in mountain regions; rare. (Eu.) 



4. P. asplenoides, Dumort. Branched, creeping or ascending; leaves 

 subimbricate, obliquely spreading, round-obovate, entire or denticulate, the 

 dorsal margin retlexed ; perianth much exceeding the involucral leaves, ob- 

 long, dilated at the truncate or ciliate apex. — In rocky rivulets; common. 

 (Eu.) 



21. MYLIA, S.F.Gray. (PI. 2.5.) 

 Leaves succubous, semi-vertical, circular, or ovate and pointed ; underleaves 

 subulate. Dioecious. Fruit terminal or pseudaxillary. Involucral leaves 2, 

 clasping ; perianth ovate-oblong, laterally compressed above a subterete base, 

 the apex at length bilabiate, denticulate. Capsule ovate, coriaceous. Elaters 

 free. Antheridia 2 in the axils of bracts clustered near the apex of distinct 

 bramhes. (Name from Mtjlius, an early botanist.) 



1 . M. Taylbri, S. F. Gray. Stems erect, nearly simple, radiculose ; leaves 

 large, convex, orbicular, entire, purplish ; cells large ; underleaves lance-subu- 

 late, entire or sul)dentate ; ])erianth terminal, oval ; calyptra finally long- 

 exserted. ( Jungermannia Taylori, Hook.) — Wet rocks, high mountains of 

 N. Eng. and N. Y. (Eu.) 



22. HARP ANT HUS, Nees. (PI. 2.?.) 

 Leaves succubous, semi-vertical, ovate, emarginate ; underleaves connate 

 with the leaves, ovate or lanceolate, 1 -toothed at ba.'^e. Dianious. Fruit on 

 short shoots from the axils of the uudeileaves, fiuallv sublateral. Involucral 



