728 MARCHANTIA.CE.ffi. (LIVERWORTS.) 



sistent. Capsule globose, exserted, pendulous, dehiscing by several revolute 

 segments. Elaters long, attenuate to each end. Spores smooth. Antheridia 

 immersed in a peduncled di.sk-like radiate or lobed receptacle. (Named for 

 Nicholas Marchant, a French botanist.) 



1. M. polymorpha, L. Thallus 2-5' long, i-H' wide, numerously 

 porose, veuulose; receptacle divided into usually 9 terete rays; peduncles 1- 

 3' high; autheridial disk crenately or palmately 2-8-lobed, on a peduncle 1' 

 high or less. Everywhere common. (Eu.) 



2. PREISSIA, Sees. (PL 22.) 



Thallus obcordate, sparingly forked, increasing by joints ; pores conspicu- 

 ous ; gemmae none. Dioecious or monoecious. Fertile receptacle hemispheric, 

 1 -4-lobed, with as many alternating shorter rib-like rays. Outer involucres 

 attached beneath the lobes, 1-3-fruited, opening outward by an irregular 

 line ; perianth obconic-campanulate, angular, unequally 4 - 5-lobed. Calyptra 

 persistent. Capsule large, distinctly pedicelled, dehiscing by 4-8 revolute 

 segments. Elaters short. Spores coarsely tuberculate. (Named for L. Preiss, 

 a German botanist.) 



1. P. commutata, Nees. Thallus 1-2' long, with conspicuous white 

 pores above, and dark purple scales beneath ; usually monoecious ; peduncle 

 i-l' high ; capsules conspicuous, dark purple ; antheridia in a peduncled disk- 

 like receptacle. (P. hemisphffirica, Cogn.) On slaty and limestone rocks, 

 from N. J. north and westward. (Eu.) 



3. FIMBRIARIA, Nees. (PL 22.) 



Thallus thickened in the middle by a keeled costa, usually conspicuously 

 porose, with dark purple scales beneath ; gemmae none. Monoecious. Recep- 

 tacle rising from the apex, conic or hemispheric, concave beneath and expanded 

 into usually 4 large campanulate 1 -fruited involucres. Perianth oblong-oval 

 or subconic, exserted half its length and cleft into 8-16 fringe-like segments. 

 Calyptra with a long style, fugacious. Capsule nearly sessile, irregularly cir- 

 cuniscissile. Elaters rather short, 1 - 4-spiral. Spores angular, subreticulated. 

 Antheridia immersed in the thallus. (Name tiomfimbria, a fringe, alluding 

 to the perianth.) 



1. F. tenella, Nees. Thallus of one or more long-wedge-shaped emar- 

 ginate divisions about 6 - 9" long, grayish-green and porose above, purple on 

 the margins; peduncle 1' high or more, usually purple ; receptacle obtusely 

 conic ; perianth white, 8-cleft. On damp ground in sandy fields or on rocks, 

 central N. Y. to Mo., and southward. 



4. CONOCEPHALUS, Neck. (PL 22.) 



Thallus dichotomous, copiously reticulate and porose, with a narrow costa ; 

 gemmae none. Receptacle conic-mitriform, membranous. Involucres 5-8, 

 tubular, 1-fruited, suspended from the apex of the peduncle; perianth none. 

 Calyptra persistent, campanulate, 2 - 4-lobed at the apex. Capsule pedicelled, 

 oblong-pyriform, dehiscing by 5-8 revolute segments. Elaters short, thick. 

 Spores muriculate. Antheridia imbedded in an oval disk sessile near the apex 

 of the thallus. (Name from KUVOS, a cone, and Ke<pa\-l), a head.) 



