LEAF-ARCHITECTURE AS ILLUMINATED BY A STUDY OF PTERIDOPHYTA. 677 



fussia* From all of these drawings it would appear that dichotomy, as expressed 

 in outline or in venation, is not an obvious character of the juvenile leaf. But 



d 



Fig. 10.— Juvenile leaves of Danoea nodosa, (x 4.) 



Fie. 11.— Young leaf of Angiopteris everfa, showing at its base, on the right, a pinna, 

 and on the left another is indicated. ( x 4. ) 



comparison of such leaves themselves, and their interpretation in the light of 

 experience from other Ferns, shows that dichotomy developed sympodially is the 

 fundamental construction of them all. 



Observations were made on young plants of Dansea nodosa, collected in Jamaica. 

 The smallest cotyledon seen is shown in fig. 10, a, and, though the outline is entire, 



* L.c, fig. 123, p. 147 ; also Buit. Ann., 2nd series, vol. vii, pi. viii. 



