Heputicw of Nortli America. ;}8 



1. M polymorpha L. Thallus usually 5 — 12.5 cm. 

 long, 1.3 — 8.8 cm. wide, canaliculate, and with numerous small 

 pores above, plicate-venulose; carpoceplialum deeply divided 

 into usually 9 terete rays; peduncles 2.5 — ^7.5 cm. high, stout, 

 pilose: involucres many-fruited; androeciuui on a naked pedun- 

 cle 2.5 cm. high or less, crenately or often palmately 2-8-lobed, 

 the lobes flat. 



Hah. — Ditches and wet places ; common. (Eu.) 

 Bih.—^yn. Hep. p. 522, 789; Hep. Europ. p. 150. 

 DeKn.— Sulliv. Mosses U. S. t. VI. 

 Exsic. — Hep. Bor.-Amer. No. 127. 



2. M. disjuncta Sulliv. Thallus 2.5—5 cm. long, O.G— 

 1.3 cm. wide, innovating from the apex; carpocephalum | cir- 

 cular, radiately 3-7-lobed, the lobes flat, cuneate, crenulate on 

 the outer margin; peduncles 2.5 cm. high; androecium large, 

 on a stout peduncle 2 — 4 mm. high, digitately parted, the divi- 

 sions elongate-oblong or linear-oblong, subentire. 



Hah. — Springy places, banks of Alabama R. near Clairborne {Sulli- 

 rnnt). 



Bib. — Mem. Amer. Acad. n. ser. Ill, p. 63. 



Delin. — Mem. Amer. Acad. n. ser. Ill, t. III. 



E.xsic. — Muse. Alleghan. No. 286; Hep. Bor.-Amer. No. 128. 



TI. PREISSIA Nees. 



Carpoceplialum hemispheric, 1-4-lobed, with as many rib- 

 like rays alternating with and shorter than the lobes, fibrous- 

 barljulate underneath. Outer involucres as many as the rays, 

 attached to the under side of the lobes, 1-3-fruited, opening 

 beneath and outwardly by an irregular line. Inner involucre 

 obconic-carapanulate, angular, unequally 4-5-lobed. Calyptra 

 persistent, rupturing obliquely at the apex. Capsule large, dis- 

 tinctly pedicelled, dehiscing by 4-8 revolute segments. Spores 

 grossly tuberculate. Elaters short, bispiral. Inflorescence 

 dioecious or moncBcious. Thallus obcordate, sparingly forked, 

 increasing by joints from the apex; pores conspicuous. Gem- 

 mcB wanting;. Named for L. PreisH, a German botanist. 



