BEYOPHYTA— HEPATICiE 



111 



structure, often being composed of only one or two cells. They 

 arise either from the margins of the leaves or from the axis near 

 its apex. 



The antheridia are stalked somewhat globular bodies which 

 are not sunk in the tissue as in Marohantia, but arise singly 

 or in groups on the shoot near its apex, in the axils of the 

 leaves. 



The archegonia are developed later, sometimes from the 

 same shoot as the antheridia. They are sometimes solitary, some- 

 times in groups, and are surrounded by a kind of involucre formed 

 either by the cohesion together of the youngest whorl of leaves, 

 or by a perichstial outgrowth resembling that of Marohantia. 

 They are produced 



directly from the apical ^^°- ^''9- 



cell or its youngest 

 segments, so that they 

 are terminal in their 

 position. Usually each 

 archegouium is pro- 

 tected also by a peri- 

 gynium. 



The histological 

 differentiation of the 

 shoot is very slight. 

 The stem possesses an 

 axial strand of cells 

 which have thin walls, 

 while the cortex is 

 made up of fairly thick- 

 walled cells. There is 

 no indication of any- 

 thing like vascular 

 tissue. The leaves are 

 simple plates of cells 

 of imiform substance, being only one cell thick. 



The sporophyte is mainly derived from the epibasal cell of 

 the first division of the oospore, the hypobasal one often not 

 developing at all, but remaining in an atrophied condition at 

 the base of the stalk of the capsule. The epibasal mass then 

 can be differentiated into the capsule and a bulky stalk or seta, 

 the lower end of which sweUs and forms a false foot (Jig. 869). 

 The archesporium is co-extensive with the endotheoium and 

 produces spores and sterile cells, usiuiUy elaters. "When it is 



Fi(j. 869. Sporogoniam of Jungermannia. 

 a. Oalyptra. t. False foot. After Sachs. 



