RICCIA. 489 



covered walls, IF. IL P. 1876. 12. On clamp limestone rocks, 

 Levens Park, Westmorland, G. Sf abler, 1870. 13. Burnfoot Hill, 

 New Galloway, ./. Mc Andrew. 15. Head of Glen Dole, Forfar, 

 J.Sadler, 1872. 



Found on the Continent and in North America. 



Ohs. — The only other British species which is without cilia 

 and has a purple margin is Riccia ir'up'eJla 1).C. ; this is smaller, 

 with narrow linear lobes, dark green antical surface, the margin 

 and postical surfiice of which are clothed with regularly imbricating 

 scales. 



Riccia (;laucescem Carr. is a ciliate species, usually much larger 

 and irregular in shape, but small forms where the cilia are not 

 so evident require careful observation to discriminate from 

 R. /jifi/rca. The description and drawings are partly taken 

 from Dr. Carrington's " New British Hepaticoe " contributed 

 to " Grevillea," Dec. 1874. 



Description oi<' PlxVTE CCXIX. — Figs. 1-3. Fronds natural 

 size. 4-7. Fronds x ?. 8. Frond x ?. 9-14. Cross-sections 

 of fronds x 16. 15. Cross-section of frond near apex x 16. 

 16-19. Spores x 250 (Dr. Carrington & W. H. P.). 



5. Riccia nigrella, JJ.C. 



JRiccia niyrella, De Candolle, Fl. Fr. v., p. 19;] (1^05); Lindenb. Monog. Rice. 



p. 4(;7, I. xxix. f. 1 (18:50). 

 Blccia lamellosa, Ralfs, MSS. ; Cooke, Brit. Hep. n. 1;}3 (1SG8). 

 Exsicc. Husn. Hep. Gall. n. DC ; Carr. k Pears. Hep. Brit. Exsicc. n. G.'>, et 2!)(>. 



Dioicous, ca?spitose, minute, dark green in colour antically : 

 clothed with dark purple, almost black, transverse, closely imbri- 

 cated semi-circular scales postically or on the postical margin. 

 Fronds stellate or sub-stellate, narrow, linear, narrowly canalicu- 

 late, margins thickened, involute, strongly so wlien dry ; radicuiose, 

 rootlets few, hyaline. Spores angular globose, dark brown, almost 

 black, slightly verruculose. 



Dimensions. — Fronds 4* mm. x 1- mm. : 35' mm. x 75 mm., 



