Rice IOC ARP US. 49 7 



aenus 55. RICCIOCARPUS, Corda. 



Ricciocarpus, Corda in Opiz Nat. (1829). 

 Riccia, Linn. Syst. 956. 



Plants obcordate, constantly dividing with growth, air-cavities 

 abundant, postical surface naked or furnished with long dentate 

 scales. Fruit immersed in the frond and not protruding on either 

 surface, at length naked by the splitting of the central groove. 

 Antheridia in a row in the middle of the frond. 



Ricciocarpus natans (Ziuh.), Corda. 



Riccia natans, Linn. Syst. Nat. ed. v. 12. p. 2 (1753). 

 Ricciocarpus natans, Corda in Opiz Nat. p. (J51 (1829). 



Dioicous, floating on water or when terrestrial forming rosettes, 

 small, pale or dark green above, jDurple below. Fronds simple, 

 obcordate or obcuneate, broadly emarginate, channelled in the 

 centre, furnished with long linear-lanceolate ribbon-like, flattened, 

 purple, serrated membranaceous processes; epidermis with numerous 

 uniform air-cavities beneath it ; texture spongy ; radiculose, root- 

 lets few, very long, hyaline, smooth within. Capsules immersed 

 in the frond about the middle in two rows. Spores brownish- 

 black, angular, strongly papillose, papillae blunt. 



Dimensions. — Fronds J to |^ inch long, segments 3" mm. 

 broad ; capsule '7b mm. diam. ; spores '05 mm. 



Hab. — Stagnant ponds, floating, or on damp margins of the 

 same. Hare. 



2. Hampshire,^///; Warner. -4,5. Near Eoss, Herefordshire, 

 B. M. WatMns. 7, 8. Thurcaston, Leicestershire, i^. T.Motf. 10. 

 Hebden Bridge, S. Gibson ; near Dringhouses, near York, JF. IFcsf. 



" Rare in Ireland. Abundant in a large boggy pool, about 

 half-way between Drogheda and Navan, near the Railway, right- 

 hand side going from Navan to Drogheda ; ditch by the side of 

 the Shannon, near Portumna, Co. Gal way. Ditches near Passy, 

 Co. Limerick, Dr. W. H. ILarccij'' — Dr. D. Moore. 



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