507 
Davallias and the Petiole of Lygodium. 
Photo 7. Transverse section of the trace of a primary branch of Davallia fumarioides which 
has just given off to the left the trace to the first secondary branch; cf. Text-fig. 7, c 2 . Slide 
No. 2154. ( x 67.) 
Photo 8. Transverse section of the trace of a primary branch of Davallia fumarioides above 
the departure of the first pair of secondary branches ; cf. Text-fig. 7, C 3 , D. Slide No. 2164. ( x 67.) 
Photo 9. Lygodium scandens. Transverse section of petiolar trace, showing the trace to the 
second primary branch going off on the left; cf. Text-fig. 1, c 4 . Slide No. 2073. ( x 46.) 
Photo 10. Lygodium japonicum. Transverse section of petiolar trace, showing the abaxial 
protoxylem enclosed by centrifugal metaxylem ; cf. Text-figs. 2 c, 3 A. Slide No. 2095. ( x 67.) 
The general resemblance between the petiolar trace and the origin of a primary branch-trace in 
Davallia fumarioides and in Lygodium scandens will be evident on comparison of Photos 3 and 9, 
while a still closer similarity can be traced between the petiolar trace of Lygodium japonicum 
(Photo 10) and a particular stage of the primary branch-trace of Davallia fumarioides (Photo j). 
These pairs of figures have been placed together on the plate to facilitate comparison. 
