MARCHANTIACE^E. (LIVERWORTS.) 727 



2. NOTOTHYLAS, Sulliv. (PI. 22.) 



Thallus orbicular, tender, laciniate and undulate or crisped, papillose-reticu- 

 late. Monoecious. Involucre sessile, continuous with the thallus, opening 

 irregularly above. Capsule very short, oblong-globose or ovate-cylindric, pedi- 

 celled from a thickened bulb, 2-valved to the middle or rupturing irregularly. 

 Elaters none, or fragmentary and inconspicuous. Spores subglobose, smooth- 

 ish. Antheridia elliptic-globose, immersed in the thallus. (Name from v&ros, 

 the back, and 6v\ds, a bag, from the shape and position of the involucre.) 



1. W. orbieulris, Sulliv. (PI. 22.) Thallus 3 - 8" wide ; capsules 1- 

 2" long, erect or decurved, wholly included or slightly exserted, of thin and 

 loose texture, with a suture on each side ; spores light yellowish-brown. (In- 

 cluding N. valvata, Sulliv.) Wet places, Canada to the Gulf. 



2. N. melan6spora, Sulliv. Thallus small, depressed or sometimes 

 cespitose, of lax texture ; capsule often without sutures ; spores dark brown, 

 a half larger. Moist ground, Ohio (Sullivant). 



ORDER 139. MARCHANTlACEJE. LIVERWORTS. 



Plant-body a thallus, dichotomous or subpalmately branching, usually 

 innovating from the apex or beneath it, more or less thickened in the 

 middle, and bearing numerous rootlets beneath and usually colored or 

 imbricating scales. Epidermis usually more or less distinct and strongly 

 porose above. Capsules globose, rarely oval, opening irregularly, pen- 

 dent from the under side of a peduncled disk-like receptacle (carpocepha- 

 Iwri). Elaters present, mostly 2-spiral. 



* Thallus plainly costate, distinctly porose except in n. 6. 

 i- Gemmae present on sterile stems. 



1. Marchantia. Gemmae in cup-shaped receptacles. Fertile receptacle 7 - 11-rayed. 

 8. Lunularia. Gemmae in crescent-shaped receptacles. Fertile receptacle cruciform. 



+- - Gemmae wanting. 

 H- Receptacle conic-hemispherical, 2 - 4-lobed ; perianth lobed or fringed. 



2. Preissia. Receptacle 2 -4-lobed, with as many alternate rib-like rays. Perianth 4-5- 



lobed. 



3. Fimbriaria. Receptacle 4-lobed. Perianth conspicuous, split into 8-16 fringe-like 



segments. 



H- -H- Receptacle more or less conical ; perianth none. 



4. Conocephalus. Thallus very large, strongly areolate. Receptacle conical, membranous. 



5. Grimaldia. Thallus small. Peduncle chaffy at base and apex. Receptacle conic- 



hemispheric, truncately 3 -4-lobed. 



6. Asterella. Thallus eporose. Receptacle conic-hemispheric, becoming flattened, acutely 



4- (1- 6-) lobed. 



* * Thallus thin, ecostate or barely costate. 

 *. Dumortiera. Receptacle convex, 2 - 8-lobed. Perianth none. 



1. MARCHANTIA, Marchantf. (PI. 22.) 



Thallus large, forking, areolate, porose, with broad diffused midrib ; gemmae 

 in a cup-shaped receptacle. Dioecious. Fertile receptacle peduncled from an 

 apical sinus of the thallus, radiately lobed. Involucres alternate with the rays, 

 membranous, lacerate, enclosing 3-6 1-fruited cleft perianths. Calyptra per- 



