CHAPTER V. 



MARCHANTIEiE AND TARGIONIE^E. 



Marchantia polymorphs Fegatella conica, Bebouillia hemi- 

 spheric^ Lunularia vulgaris. Targionia hypophylla. 



The growth of the Marchantieaa and Targionieae resem- 

 bles in its principal phenomena that of Pellia, Riccia, 

 and Anthoceros. The essential circumstance, viz., the 

 origin of each new shoot by the amalgamation of three 

 shoots, which are developed in one of the two in- 

 dentations of the fore edge of an older shoot, is in these 

 plants, especially in the genera Lunularia and Fegatella, 

 more clearly marked than in any others* 



The vegetative organs of Marchantia polymorpha, Fega- 

 tella conica, Bebouillia hemispherica, Lunularia vulgaris, and 

 Targionia hypophylla exhibit great similarity in development 



* The rudiments of those shoots of Fegatalla conica which are to be deve- 

 loped in the early spring originate in the preceding October; on the right and 

 left of a nearly hemispherical mass of cellular tissue, situated at the bottom 

 of one of the two indentations of the fore edge of the fully developed shoot of 

 the next higher order, there are formed two smaller, almost conical shoots, 

 which, by amalgamating with the one between them, form the bud of the new 

 shoot. The shoot grows slowly in a longitudinal direction until the commence- 

 ment of winter ; the fore edge of the median shoot becomes, at the same time, 

 contiuually wider (PI. XVI, fig. 1, middle of November). After the coldest 

 months are over there is formed on either side of the median lobe the rudi- 

 ment of a new shoot, which has already attained a tolerably perfect condition 

 at the time when the longitudinal expansion of the oldest hinder cells of the 

 shoot formed at, the commencement of winter begins to cause the latter to 

 protrude out of the indentation of the edge of the stem-joint of the previous 

 year. The shoot whose longitudinal expansion commences, appears at this 

 time as if bent upwards ; a thick-fleshed, small mass of cellular tissue, already 

 slightly furcate at the fore edge by the commencement of the longitudinal 

 development of the shoots of a new order. The lateral margins of the shoot 

 are bent strongly inwards, and it is closely folded together in its median line. 



