II EPA TICAE. 



H7 



beginnings of the lateral margins facing towards each other of the two daughter- 

 shoots, which separate from one another as growth continues. When the bifurcating 

 shoots grow longer, the middle lobe appears as the re-entering margin of the older 

 bifurcation (Fig. 96,/). Symphogyna and Umbraculum have shoots, the rudiments of 



•u,. 95. Aiieura inulli/ida. Apex of a thallus in tlie act of dividing or branching ; v,'u\, im apical cells of the 

 : shoots formed by the branching of the primary apex, yl/, , M^ intermediate lobes separating the apices of the 



which appear at the growing point and on the ventral (under) side of the thallus also, 

 and the same proceeding is observed in many Marchantieae {vide infra). The filiform 

 stem of the foliose Jungermannieae ends in a bud as a more or less projecting vegeta- 

 tive cone with an apical cell which is a very convex three-sided pyramid. The branch- 

 ing is here always monopodial and very varied, as will be shown more fully below. 



The arrangement of the cells 

 in the apex is different in dif- 

 ferent genera. While the foliose 

 forms have always, as has been 

 said, an apical cell which is a 

 three-sided pyramid, the thalloid 

 forms, Metzgeria for instance and 

 Aneura,\\2C^^ what is known as the 

 wedge-shaped apical cell or some 

 complicated forms of it, into 

 which we must not enter further 

 here since they show nothing 

 essentially characteristic. 



Asexual propagation is often 

 effected in the Hepaticae by the 

 dying away of the stem behind, by 

 which the shoots lose their con- 

 nection and become independent; 

 adventitious shoots from cells of older portions of the margin or of the midrib, where 

 as in JSIetzgeria there is a midrib, become detached in the same way. I.eitgeb says that 

 these adventitious shoots of the midrib oi Metzgeria may also be formed endogenously. 

 In foliose forms adventitious shoots are found on older leaves and on the stems. 

 Copious propagation by gemmae occurs in many species and is very characteristic ; 



L 2 



Fig. 96. Metzgri-ia/urcnta, magn. about i 

 right, the lower to the left of the figure ; in the 

 //wing-like expansion formed of a single layer 

 with the branching of the plant (middle lobes). 



times, the upper side seen to the 

 midrib, s, s' , s" the apical region, 

 )f cells, f ./"./"' its; development 



