268 Davie . — Structure and Affinities of Per anema and Diacalpe. 
Fig. 3. Successive sections through the petiole, showing the departure of the vascular supply to 
the basal pinnae, ad., adaxial strands ; m., median main strand ; ss., subsidiary strands ; cc., com- 
missural strands ; pp., pinna-trace strands, x 8. 
Fig. 4. Series of diagrams illustrating the insertion of the leaf-trace bundles on the dictyostele 
in various Ferns. 1. Peranema cyatheoides. Portion of dictyostele seen from within, showing leaf- 
gap and the bundles from the leaf subtending this gap. 11. The same leaf-gap viewed from without. 
in., median main leaf-trace strand ; ad., adaxial main strands. III. Another leaf-gap with the bundles 
from the leaf opposite to it (//.), and with parts of the traces from the two leaves obliquely next above 
(aa) and (bo), iv. Lomaria Spicant. Dictyostele at leaf- gap, with the three leaf-trace bundles, 
v. Onoclea orientalis. Dictyostele at leaf-gap, with the two leaf-trace bundles, vi. Athyrium jilix- 
foemina . Dictyostele at leaf-gap, showing the insertion of the leaf-trace. It leaves the dictyostele 
as an undivided trace and in the base of the petiole becomes divided into two strap-shaped strands. 
All considerably magnified. 
Fig. 5. Transverse section through the young shoot of Peranema , just below the apex, showing 
the first lignification in the stele, x 450. 
Fig. 6. Transverse sections through the adaxial main strands of the leaf-trace, showing the 
‘ extramarginal ’ type of supply to the basal pinna. All x 76. (a) Strand below the level of the 
pinna, showing the hooked end, from which the supply goes off to the pinna. ( b ) Pinna-supply in 
process of being given off. ( c ) Reconstituted adaxial strand (ad) with pinna-trace ( p ) passing out to 
the pinna. 
Fig. 7. Successive transverse sections through the rachis of a basal pinna to show the develop- 
ment of the pinna- trace, from the point of departure from the petiolar adaxial strand (1) up to the 
fully constituted condition (xi). All about x 8. 
Fig. 8. Palea from young leaf-stalk, x 3. 
Fig. 9. Hair from the rachis of the frond, showing glands on the curved portion, x 76. 
Fig. 10. Gland from the palest of a young frond, x 450. 
Fig. 11. Glands from the surface of the mature petiole, x 450. 
Fig. 12. Transverse section through a young pinna, showing marginal segmentation of the usual 
Leptosporangiate type, x 450. 
Fig. 13. Longitudinal section through the stalked sorus, showing the elongated receptacle with 
its vascular supply and the mixed arrangement of the sporangia, x 76. 
Fig. 14. Longitudinal section through the sorus, showing the elongated receptacle and the mixed 
succession of sporangia. The indusium is two-layered at its base, x 76. 
Fig. 15. Longitudinal section through the sorus, showing the way in which the rim of the 
indusium is tucked in on the lower side, close to the point of insertion of the stalk, x 76- 
Fig. 16. Section through a mature sporangium, showing the slight obliquity of the annulus. 
X 150. 
Fig. 17. Section through the stalk of a mature sporangium, x 150. 
Fig. 18. Almost mature sporangium, showing the continuation of the cells of the annulus past 
the stalk, x 225. 
Fig. 19. Mature sporangium, showing the slightly oblique insertion of the annulus, x 150. 
Fig. 20. Sporangium, showing the indurated cells of the stomium. x 150. 
Fig. 21. Spores of Peranema, showing the papillate pits formed by the perispore. x 450. 
Fig. 22. Section through a mature sporangium of Diacalpe , showing the insertion of the annulus 
and the markings on the spores, x 150. 
Fig. 23. Mature sporangium of Diacalpe aspidioides, showing a hair on the stalk, x 150. 
