©ostelsia 69 



niacese a portion, and in some forms 

 the greater part, is contributed by the 

 tissues derived from the epibasal cell. 

 All the moss sporophytes possess a 

 nursing-foot which is developed from 

 the hypobasal cell with additions of 

 epibasal tissue. Passing from the con- 

 dition in Marchantia to that seen in 

 the more highly differentiated spor- 

 ophytes of the Bryophyta, there seems 

 to be a gradual diminution in the rel- 

 ative size and importance of the hypo- 

 basal portion of the foot, the absorptive 

 function being discharged almost wholly 

 by the more bulky epibasal portion, 

 as may be especially well seen in 

 Sphagnum, In the Lycopodinse the 

 hypobasal portion has abandoned its 

 primary absorptive function and ac- 

 cepted another connected with the 

 change in oosperm orientation. The 

 functional nursing-foot in the Lycopo- 



