520 



LIFE-HISTORIES 



Fig. 341, III. — Umbrella-liverwort. Top of arehigoniophore (1) cut ver- 

 tically to show the stalked sporophytes of different ages: the two inner 

 ones are still within the enlarged wall of the archegonium; the right- 

 hand one has protruded on its stalk leaving the archegonial wall as a 

 sheath (calyplra) at the base of its stalk; wdiile the left-hand one has 

 burst open and is shedding its spores and elaters. (Atkinson.) 



Fig. 341, IV. — Umbrella-liverwort. ni<', cluster of young spores; sp, spore. 

 An elater. A piece of the same, showing the elastic spring-like spiral 

 thickening within. All highly magnified. (Atkinson.) 



