JTJNGERMANXIACEAE. 



459 





1. Cephaloziella byssacea (Both) Warnst. CEPHALOZIELLA. 

 (Figt 505.) Plants green, often more or less pigmented with 

 reddish or purplish, growing in more or less compact mats or mixed 

 with other plants. Leaves distant to subimbricated, quadrate, 

 divided to the middle or beyond into two ovate-lanceolate, mostly 

 acute divisions, entire; leaf-cells 10-15 /u in diameter, slightly or 

 not at all thickened; underleaves usually distinct, lanceolate to 

 ovate, sometimes shortly bifid ; inflorescence dioecious ; androecia 

 composed of from six to twelve pairs of imbricated bracts, often 

 proliferating; arehegonia borne on an elongated branch; bracts 

 and bracteole bifid with sharply dentate lobes, more or less coales- 

 cent; mouth of perianth crenulate, [Jungermannia byssacea 

 Roth.] 



On moist soil, Devonshire Marsh. Widely distributed in Europe, 

 Asia, and North America. The Bermuda specimens are in poor condi- 

 tion and are doubtfully referred to the present species. They have 

 already been listed from Bermuda as Cephalozia divaricata (Sm.) 

 Dumort., a synonym of Ceplialoziclla byssacea. 



4. ODONTOSCHISMA Dumort. 



Stems prostrate, sparingly and irregularly branched, the 

 branches lateral or ventral, often fiagelliform. Leaves sueeubous, 

 obliquely attached, undivided, entire, and usually rounded or 

 truncate at the apex. Leaf-cells usually with more or less thick- 

 ened walls. Underleaves present but often minute and short- 

 lived. Antheridia borne in the axils of imbricated and bifid 

 bracts, the latter forming androecia of variable length, not pro- 

 liferating. Arehegonia borne on short ventral branches, the ter- 

 minal portion swelling after fertilization. Bracts and bracteoles similar, 

 usually bifid, not eoalescent. Perianth triangular-prismatic with one keel 

 ventral, the mouth subcrenulate to ciliate, constricted, irregularly sinuate or 

 lobed. Gemmae unicellular or bicellular. [Greek, split tooth,] Species about 

 25, largely tropical. Type species: 0. Spliagni (Dicks.) Dumort. 



1. Odontoschisma prostratum (Sw.) Trevis. 

 PROSTRATE ODONTOSCHISMA. (Fig. 506.) Plants 

 pale green, often more or less pigmented with 

 brownis-h, growing in depressed mats or creeping 

 among other plants ; branches all ventral, some of 

 them flagelliform. Leaves distant to loosely imbri- 

 cated, orbicular to oblong, about \" long, median 

 leaf-cells about 20 /j. in diameter, thin-walled but 

 with distinct trigones; marginal cells (in from 

 one to four rows) forming a distinct border with 

 walls uniformly thickened; underleaves minute; 

 perichaetial bracts and bracteoles bifid about one 

 half with slender acuminate and subentire lobes ; 

 mouth of perianth entire to short-setulose. [Jun- 

 germannia prostrata Sw.] 



On moist soil, Devonshire and Paget Marshes. 

 Widely distributed from Massachusetts to Florida ; 

 also in tropical America. Easily distinguished by its 

 sueeubous, undivided leaves. 



