BRYOPHYTA -HEPATIC.E 



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 Marchantia, 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 perichaetial outgrowth resembling that of Marchantia. 

 They are produced 

 directly from the apical 

 cell or its youngest 

 segments, so that they 

 are terminal in their 

 position. Usually each 

 archegonium 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 uniform 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 swells and forms a false foot (fig. 869 j. 

 The archesporium is co- extensive with the endothecium and 

 produces spores and sterile cells, usually elaters. When it is 



Fiij. 869. Sporogouium of Jungerniannia. 

 a. Calyptra. b. False foot. After Sachs. 



