430 Bower. — Studies in the Phytogeny of the Filicales. 
Fig. 2. Sections of young pinnae of Matteuccia intermedia , C. Chr. d-g are cut transversely, 
h is a longitudinal section. The sori are all separate and intramarginal, while the segmental 
margin of the pinna grows directly into the protective 1 indusial flap ’. x 125. 
Fig. 3. Sections of the young pinnae of Blechnum discolor , Keys, 0, a very young wing of 
a pinna, showing regular marginal segmentation. b } c, d, successively older pinnae, showing the 
relation of origin of the indusium, or phyletic margin, to the segmental margin ( m ) of the wing. 
e , slightly older, with basipetal sorus forming, f \ older still, with vascular commissure and 
vein shaded, g, an older wing, with sorus showing slightly mixed condition, h , section of a 
fertile pinna, showing that both sorus and commissure are interrupted, for they are absent from the 
section. In b-e , the indusium is indicated by i. f, g, h are orientated naturally, but a-e are 
inverted, a-f x 125 ; g, h x 50. 
PLATE XXIII. 
Fig. 4. Sections illustrating the development of the indusial flap and sorus in Blechnum tabulare y 
Kuhn, a , b show a segmentation which indicates that the origin of the flap is truly marginal. 
c-f indicate that the flap originates from a point which is intramarginal, g shows a later stage, 
with a sorus of basipetal sequence, h is an occasional example of the mixed character which may 
supervene later. All the drawings x 125. 
Fig. 5. A single fertile pinna of Blechnum lanceolatum , Sturm, x-y shows the plane in 
which the section Fig. 6, a , might have been cut. X 6. 
Fig. 6. Blechnum lanceolatum , Sturm, a shows a fertile pinna in transverse section ; no 
obvious flange is present ; the section came from the middle region of the pinna, b is part of a 
similar section, showing a vascular strand passing to the upper surface, c-g, successive stages of 
development of the wings of the pinna. For details see text, a, b x 50 ; c-g x 125. 
PLATE XXIV. 
Fig. 7. Blechnum attenuatum (Sw.), Mett. a-d, successive stages in development of the 
wing of the pinna, i is the indusial flap ; m is the flange ; h is the young hydathode. Section e 
shows a mature pinna in transverse section, a-d x 125; e x 8. 
Fig. 8. Blechnum V Herminieri (Bory), Mett. Similar sections showing the relation of origin 
of the relatively small flange and the indusium. a-c x 125 ; d x 50. 
PLATE XXV. 
Fig. 9. Blechnum spicant (L.), Wither. Tip of a fertile pinna, showing the venation in its 
relation to the distal end of the fusion-sori. The commissure appears to be a mere joining up of the 
anadromic branches of the dichotomous veins, x 6. 
Fig. 10. Blechnum spicant (L.), Wither. Sections showing successive stages of development 
of the flange and indusium. x 125. 
Fig. 11. Similar sections from the pinna of Blechnum capense (L.), Schlecht. In a the 
segmentation is particularly clear, and the intramarginal origin of the indusial flap, x 125. 
Fig. 12. Blechnum brasiliense, Desv. Similar sections, showing an extreme intramarginal 
origin of the indusial flap and sorus. x 125. 
PLATE XXVI. 
Fig. 13. Similar sections from the pinna of Blechnum Fraseri (A. Cunn.), Luerss. a-e x 125 ; 
/ x 50- 
Fig. 14. Blechnum Patersoni (R. Br.), Mett. Similar sections showing the segmentation, the 
intramarginal origin of the indusial flap and sorus, with its mixed condition, a-e x 125. 
PLATE XXVII. 
Fig. 15. Blechnum penna-marina (Poir), Kuhn. Sections of the pinna, of which a and b are 
transverse, and c longitudinal. The relations of origin of the relatively small flange and of the 
indusial flap and sorus are as before, but the receptacle is flat, and widely spread in an Acrostichoid 
manner, a-c x 125; b x 50. 
Fig. 16. Blechnum Jiliforme (A. Cunn.), Ettings. Similar sections, showing the segmentation 
and origin of the indusial flap and sorus. In e the flange is present, but small. In f g it appears to 
be merely vestigial, a-f x 125 ; g x 50. 
