36 Illinois State Laboratory of Natural Historij. 



immersed in the apex of the lobes at the sinus, covered by a 

 closer and more sharply papillose epidermis. Thallus weak, 

 moderately thickened in the middle, bifid and sinuate-continu- 

 ous from the apex, obscurely areolate above, concolorous or 

 often purple, obscurely squamulose along the costa underneath, 

 the scales minute and evanescent. Gemmae wanting. 



1. D. rupestris Nees. Thallus 0.6 — 1.3 cm. long, 2 — 6 

 mm. wide, the margins membranous; carpocephalum small, 

 semiglobose, 1-4-fruited; peduncle about 2.5 cm. high, spar- 

 ingly involucrate at the base, barbulate at the apex; involucres 

 1-fruited, short, thin crenulate; spores tuberculate; elaters bi- 

 spiral. (Grimaldia rupestris Lindenb.) 



Hab. — Calcareous or slaty rocks, Ontario {Macoun), O. {Miss Biddle- 

 come), Central and Northern N. Y. (Eu.) 



JBi6.— Syn. Hep. p. 553, Hep. Europ. p. 156. 

 Exsic. — Hep. Bor.-Amer. No. 134. 



VI. CRYPTOMITRIUM Aust. nov. gen. 



Carpocephalum on a peduncle arising from a marginal 

 sinus, large, peltate, slightly convex and papillose above, with 

 costa-like rays extending about half way toward the plane, 

 naked, crenate margin and tuberously thickened from the end, 

 flattish and naked beneath. Both involucres wanting. Calyp- 

 tra very obscure or ephemeral. Capsules 4-7, large, pale, ob- 

 liquely depressed, globose, immersed between the rays and 

 closely adherent to the walls of the cavity, or at length partly 

 emergent through an irregular longitudinal slit, dehiscent near 

 the apex by a very small, irregular, oblique, brownish opercu- 

 lum, the orifice becoming very large and shortly lacerate. 

 Spores very small, coarsely rugose and reticulate. Elaters very 

 long and slender, attenuate at the ends, tortuous, bispiral. 

 Thallus obcordate, cespitose-imbricate, thin and barely costate, 

 eporose above, sparingly rooted, usually purplish and very im- 

 perfectly squamulose beneath. Gemmse wanting. Name from 

 Gr. kniptos, concealed, and niitrion^ a turban. 



1. O. tenerum Aust. Thallus 0.6 — 1.3 cm. long, striate 

 or venulose-lacunose, crenulate on the margin, very slightly 

 thickened iu the middle, the cuticle beneath breaking up into 



