RICC1A. 



[ 660 ] 



RIMULINA. 



permanently encloses the sporange as an 

 adherent epigone, bearing a persistent style- 

 like neck (figs. 621, 622). The antheridia 



Fig. 620. 



Eiccia fluitans. 



Lower surface of a fragment of the frond, with three 

 imbedded sporanges projecting, their orifices being on 

 the upper surface. 



Magnified 5 diameters. 



are globose sacs contained in special cavities, 

 the orifices of which, narrowed into a neck, 

 project as short processes from the surface 

 (cuspides). The epigone being adherent to 

 the sporange, the spores appear to lie im- 

 mediately in the cavity of the former when 



Fig. 621. 



Fig. 622. 



Eiccia fluitans. 



Fig. 621. Vertical section through the frond and spo- 

 range contained in its substance. 



Fig. 622. Sporange, with persistent epigone, extracted 

 from the frond. 



Magnified 25 diameters. 



ripe ; they are unaccompanied by elaters, and 

 escape by irregular rupture of the epigone. 

 Several species occur in Britain. 



* Terrestrial. 



It. glauca, L. Frond without membran- 

 ous scales below, fleshy, ovate-oblong, two- 

 to three-lobed, 1-2 to 1" in diameter, the 

 divisions dichotomous, growing in orbicular 

 tufts, surface smoothish, punctate, glaucous 

 green. On banks. 



jR. crystallina, L. Differing from the 

 last chiefly in larger size and lighter colour, 

 and having large cavernous air-cells opening 

 widely on the upper surface. Damp mould. 



** Aquatic. 

 R.Jluitans, L. (fig. 620). Fronds with- 



out scales below, 1-2 to 2" long, repeatedly 

 forked, segments linear, notched at the 

 ends ; when placed on damp earth it pro- 

 duces radical hairs, (fig. 621-2). Stagnant 

 water. 



-R. natans, L. Fronds with long reticu- 

 lated scales below, obcordate, 1-2" long, or 

 with the two lobes again divided; scales 

 of the lower surface purple. On stagnant 

 pools. 



BIBL. Hook. Br. Fl. ii. pt. 1. 102 ; Bis- 

 cholf, Nova A.cta, xvii. 909 ; Lindenberg, 

 ibid, xviii. 361 ; Hofmeister, Vergl. Unters. 

 43 ; Kny, Jahrb. wiss. Bot. v. : Tr. Mic. Soc. 

 1880, iii. 125. 



RICCIE'^E. A tribe of Liverworts or 

 Hepaticae, consisting of delicate, green, 

 membranous fronds, spreading on the ground 

 or floating on water. The fruits are always 

 sessile on the frond, more or less imbedded 

 in its substance according to the thickness ; 

 the spores are unaccompanied by elaters. 



Synopsis of British Genera. 



Spharocarpus. Archegones dorsal, on a 

 lobed membranous frond, sparingly aggre- 

 gated. Perichsete obtuse! v conical or pear- 

 shaped ; perforated at the summit, con- 

 tinuous with the frond. Perigone wanting. 

 Epigone crowned by the deciduous style. 

 Sporange at length free, indehiscent. 



Riccia. Archegones immersed in the 

 frond, scattered, neither emergent nor ex- 

 posed on the surface until burst. Perichsete 

 and perigone undistinguishable. Epigone 

 crowned by the enlarged, long, persistent 

 style, adherent to the sporange. Sporange 

 bursting irregularly. 



RICE. This grain is produced by the 

 grass called Oryza sativa. The seed is 

 remarkable for the hard character of the 

 albumen, which is explained at once when 

 we examine a section under the microscope 

 (PI. 46. figs. 12 & 13). The ceUs are filled 

 with very small starch-grains, which are 

 packed so closely that they assume a paren- 

 chymatous form and present the appearance 

 of a continuous tissue (as in maize). The 

 cohesion of the starch-granules is the cause 

 of the peculiar grittiness of rice-flour. See 

 STARCH. 



RIMULA'RIA, Nyl. A genus of Leci- 

 deinei (Lichenaceous Lichens). 



Char. Apothecfa black, rounded, de- 

 pressed in the centre, dehiscing by a sub- 

 radiate fissure ; spores simple. (Leighton, 

 Lick. Flora, 438.) 



RIMULl'NA, D'Orb. A Nodosarine 



