A LEAFY LIVERWORT. 



Porella. 



BRYOPHYTES; HEPATIC^; JUNGERMANNIALES. 



PRELIMINARY. 



Porella is common in temperate regions, appearing 

 as a moss-like growth upon logs, tree-trunks, etc. It 

 lies almost prostrate, with the tips of branches somewhat 

 turned up. It can undergo extreme drying and retain 

 its vitality. Material collected for study may be pre- 

 served by drying or in the ordinary preserving fluids. 

 For the study there should be specimens showing the 

 vegetative structures, and also some showing reproduc- 

 tive organs. The latter may usually be detected by the 

 tufted arrangement of the leaves at the tips of branches 

 on which there are reproductive organs. The archegonia 

 and antheridia are not borne on the same branches. 



LABORATORY WORK. 

 GROSS STRUCTURE. 



With a few specimens in hand and by use of a hand-lens 

 observe: 



i. The central axis or stem of the plant from which arise: 

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