"p 





NOTES— 



The actual sizes of the specimens from which these figures 

 were sketched is indicated by the vertical line beside each. 

 No. 1 is the earliest form of the prothallium ; No. 2 : As 

 growth proceeds the frontal sinus becomes deeper and wider ; 

 No. 3: By the growth of the two lobes a similar sinus is 

 formed behind, with a bending up of its margin ; No. 4 : The 

 first indication of a frond, protruding from the underside ; 

 No. 5 : Underside about same period as No. 4, showing frond; 

 No. 6 : Reduced figure with first frond expanded ; No. 7 : 

 With two fronds : plant about eight months old. 



[To face p. 45. 



