Bower. — Studies in the Phytogeny of the Filicales. 391 
region shows relatively few meristeles, in accordance with the scattered dis- 
tribution of the leaves ; in this it resembles B. penna-manna : the origin of 
the root-traces and leaf-traces is the same, the latter consisting also of only 
two strands. But in the climbing region the leaves are more crowded, and 
the axis larger, while the ring of meristeles shows more numerous gaps, and 
the meristeles themselves are very large, with bulky xylem. Still the 
Blechnum- type is maintained ; it is only the size and the complexity of the 
system, not its plan, that is changed. It is important that this likeness to 
other Blechnums should be demonstrated, as in certain external features 
this species is so divergent from the genus at large. 
The development of the fertile pinna resembles that of B. Patersoni. It 
starts with the usual marginal segmentation (PI. XXVII, Fig. 16, a). The 
indusial flap is initiated in an intramarginal 
position (Fig. 16, b , c). But as the marginal 
activity is not continued, the flange remains 
small (Fig. 1 6 ,d,e), and in some cases may 
not project appreciably from the curved sur- 
face of the pinna (Fig. 16,/). The marginal 
cell itself takes sometimes a glandular appear- 
ance, which together with its position and 
shape serves to mark its identity, which 
might otherwise be missed. Meanwhile the 
cells on the upper surface of the pinna en- 
large, and become watery. The receptacle, 
which is now covered in by the indusial flap, _ - 
, ..... . (A. Cunn.), Ettingsh. a, transverse 
produces sporangia, which show various ages section from a climbing stem ; b, from 
intermixed and are spread over a fairly a creeping rhizome, x 6. 
wide area, as in B. penna-marina. Later, the 
thin watery cells in the neighbourhood of the flange begin to collapse ; 
their thin outer walls are thrown into folds, with the effect that the margin 
is inverted, as may be observed in the mature pinna (Fig. 16, g). 
It appears from these data that the pinna is of the type of B. Patersoni ; 
that it shows slightly ‘ Acrostichoid ’ characters ; that the flange is liable to 
be arrested, and appears indeed to be merely vestigial, as is seen in 
Fig. i 6 ,f,g- As an ‘Acrostichoid 5 type it is not so advanced as B. penna- 
marina in point of spread of the sorus. But it will be seen that in the 
general characters of the plant it shows a nearer approach to the Steno - 
chlaena type than any other species of the genus that has been investigated. 
Stenochlaena sorbifolia (L.), J. Sm. 
This Fern, which is very widely spread throughout the tropics, is main- 
tained as a representative of the substantive genus Stenochlaena^ J. Sm., by 
Dr. C. Christensen. It has undergone unusual vicissitudes of nomenclature, 
Text-fig. 10. Blechnum filiforme 
