730 MARCHANTIACE^E. (LIVERWORTS.) 



1. D. hirsilta, Nees. Thallus 2-5' long, 6-9" wide, deep green, be- 

 coming blackish, entire on the margins, naked above or with a delicate ap- 

 pressed pubescence ; direcious ; receptacle many-fruited, the margin closely 

 hairy ; peduncle rather long, chaffy at the apex. On moist calcareous rocks, 

 Easton, Penn. (Porter), and southward. 



8. LUNULARIA, Micheli. (PI. 25.) 



Thallus oblong with rounded lobes, distinctly areolate and porose, with im- 

 bricate sublunate scales beneath ; gemmae in crescent-shaped receptacles. 

 Dioecious. Fertile receptacle usually cruciately divided into 4 horizontal seg- 

 ments or involucres, which are tubular, vertically bilabiate and 1-fruited. 

 Calvptra included, persistent. Capsule exserted, 4-8-valved. Elaters short, 

 very slender, mostly free. Spores nearly smooth. Antheridia borne in the 

 apical sinus of the thallus. (Name from lunula, a little moon.) 



L. VULGAKIS, Kaddi. Thallus 1-2' long, forked, innovating ^from the 

 apex, with a somewhat diffuse costa; peduncle very hairy, 1-1^' long. 

 Introduced into greenhouses ; always sterile, but easily recognized by the 

 characteristic receptacles. (L. cruciata, Dumort.) (Int. from Eu.) 



ORDER 140. RICCIACE^E. 



Plant-body a dichotomously branching thallus, terrestrial or aquatic. 

 Capsules short-pedicelled, or sessile on the thallus, or immersed in its 

 substance, free or connate with the calyptra, globose, at length ruptur- 

 ing irregularly. Calyptra crowned with a more or less deciduous point. 

 Elaters none. Spores usually angular, reticulate or muriculate. An- 

 theridia ovate, immersed in the thallus in flask-shaped cavities with 

 protruding orifices (ostioles). 



1. Riccia. Capsule immersed in the thallus. Involucre none. 



2. Sphferocarpus. Capsule sessile on the thallus. Involucre inflated-pyriform. 



1. RICCIA, Micheli. (PI. 22.) 



Thallus at first radiately divided, the centre often soon decaying ; the divis- 

 ions bifid or di - tri-chotomous, flat or depressed or channelled above, usually 

 convex and naked or squamulose beneath ; margins naked or spinulose-ciliate ; 

 epidermis usually distinct, eporose ; air-cavities evident or wanting. Capsule 

 immersed, sessile. Calyptra with a persistent style. Spores alveolate or mu- 

 riculate, usually flattened and angular. (Named for P . F. Ricci, an Italian 

 nobleman, patron of Micheli.) 



1 . LICHENODES. Fruit mostly protuberant above ; spores about 84/u. broad, 

 issuing through openings in the upper surface of the thallus ; terrestrial spe- 

 cies (on damp, usually trodden or cultivated ground), without air-cavities. 



* Thallus naked, without cilia or scales. 



1. R. Frostii, Aust. Thallus orbicular, 6-12" broad, thinnish, grayish- 

 green, the apex and narrowly membranous margins sometimes purplish, mi- 

 nutely pitted ; divisions linear or subspatulate, subtruncate and slightly 

 emarginate ; rootlets smooth or obsoletely papillose within ; capsules very 

 prominent beneath ; spores barely 50 n broad, nearly round, somewhat mar- 

 gined, with depressed sides when dry, fuscous. Ohio, 111., and westward. 



