504: JUNGBKMANNIACEAE. 



from the floors of the ehamberSj the filaments mostly three or four cells long; 

 epidermal pores bounded by several superimposed layers, each usually composed 

 of four cells. Ventral scales variable, some divided into a basal portion and an 

 appendage. Inflorescence dioecious. Antheridial receptacle terminal on a 

 thallus-branch, flat or slightly convex, more or less lobed, borne on a somewhat 

 elongated stalk with two rhizoid-furrows. Carpoeephalum arising from the ex- 

 tremity of a thallus-branch, composed of a flat or convex central portion from 

 which four to ten rays spread out, often unsymmetrically, the rays terete or 

 flat; stalk mth two or four rhizoid-furrows; archegonia (and sporophytes) 

 in radiating groups between the lobes, each group enclosed by a membranous 

 involucre consisting of two folds with fringed margins; pseudoperianth (around 

 each sporophyte) tubiilar, membranous, with an open, irregularly cleft mouth. 

 Capsule without a lid, splitting into from four to eight irregular teeth; cells 

 of wall with ring-like thickenings. Gemmae discoid, several cells thick in the 

 middle and with the growing points, borne in circular, cup-like conceptacles. [In 

 honor of Nicholas Marehant, director of the ducal garden at Blois, died 1678.] 

 About fifty species, mostly tropical. Type species: Marchantia polymorpha L. 



1. Marchantia domingensis Lehm. & Lindenb. Pug. 6: 22. 1834. 



Thallus pale to dark green, mostly 2-3 cm. long and 4-6 mm. wide, flat or 

 slightly furrowed, sinuate along the margin. Ventral scales more or less pig- 

 mented, in two longitudinal rows on each side of the middle, those of the inner 

 row with broadly lanceolate to ovate, toothed appendages; antheridial recep- 

 tacle deeply lobed, the lobes mostly four to six, palmately spreading; carpo- 

 eephalum deeply rayed, the rays mostly seven, not cylindrical; spores spherical 

 about 28 /i in diameter, with low irregular ridges; elaters bispiral; gemmae- 

 conceptacles closely short-ciliate. 



Along a drain, Fort Charlotte, New Providence : — southern I'nited States ; West 

 Indies ; Mexico ; Central America and Venezuela. Previously listed from the Ba- 

 hamas as M. chenopoda L. Santo Domingo Maechantia. 



Order 2. JUNGERMANNIALES. 



Gametophyte a prostrate, strap-shaped, dorsiventral thallus or more or 

 less clearly differentiated into stem and leaves, showing slight tissue differ- 

 entiation, destitute of air-spaces. Rhizoids all with smooth walls. An- 

 theridia in deep depressions or superficial and usually protected by scales 

 or leaves, sometimes scattered, sometimes grouped together in more or less 

 definite receptacles or androecia. Archegonia superficial but usually more 

 or less protected by scales or leaves. Sporophyte differentiated into cap- 

 sule, stalk, and foot, the capsule splitting irregularly at maturity or more 

 commonly into four equal valyes; elaters always present. 



Family 1. JUNGERMANNIACEAE Dumort. 



JUNGEEMANNIA FAMILY. 



Plant body usually prostrate or ascending, dorsiventral, differentiated 

 into stem and leaves; branches lateral or ventral; leaves normally in three 



