THE HIGHER CRYPTOGAMIA. 97 



form of the organ becomes similar to that of the arche- 

 gonium of a moss. 



Biccia glauca not unfreqnently produces gemmae in the 

 middle of the tissue of the older shoots — small, fleshy masses 

 of cellular tissue, rilled with granular mucilage. Their out- 

 line resembles that of germ-plants ; there is, however, the 

 material distinction that the two lateral portions of the fore 

 edge are not formed at an earlier period than the middle 

 one, or, to speak more accurately, the middle shoot 

 does not, during the formation of the lateral ones, continue 

 in its lowest stage of development, but it forms a prominent, 

 flattened, conical point at the time when the lateral por- 

 tions begin to protrude themselves. The arrangement 

 of the cells agrees with that of the shoots of perfect 

 plants. GeminaB which remain long surrounded by the 

 tissue of the stem exhibit the internal disintegration of 

 the tissue which I have figured in Anthoceros and 

 Blasia. The commonest of all liverworts is, strange to 

 say, one of the least known. The numerous investigations 

 and figures of Riccia relate almost exclusively to the organs 

 of fructification (Schmidel, in ' Icones,' t. xliv, xlv ; Hed- 

 wig, 'Theoria generationis, 5 ed. ii, 7, 31; BischofF, ' N. 

 A. A. C. L.,' t. xvii, p. ii, fig. 911//; Lindenberg's large 

 monograph in vol. xviii of the last-mentioned Proceedings ; 

 and lastly, Unger, ' Linnsea,' 1839). The erroneous notion, 

 that a very low state of development of the fruit must be 

 accompanied by an equally low state of development of the 

 vegetative organs, seems to have prevented the accurate 

 investigation of the phenomena of growth in Riccia, which, 

 in comparison with Anthoceros and Pellia, are very com- 

 plicated. Lindenberg expressly and repeatedly denies to 

 the genus that higher organization, and even the leaves, 

 which he figures most distinctly in very many species. The 

 widely spread notion that the growth of Riccia is radiate, 

 proceeding in all directions from a common median point, 

 may be disproved by the examination of any clod of earth 

 taken from any stubble field in autumn where Riccia 

 glauca has begun to germinate. 



Riella Reuteri, Mont. — Amongst the various forms of 

 liverworts, Montagne's genus Riella (' Ann. Sc. Nat.,' 3rd 



7 



