308 Bower . — Studies in the Phytogeny of the Filicales . 
of Woodsia , which bring forward some welcome characters for comparison 
from the gametophyte generation. In particular he draws attention ( 1 . c., 
p. 385) to the characteristic multicellular hairs on the under side of the 
cushion in the Cyatheaceae, and shows that similar hairs are present in 
Diacalpe , and also in Woodsia. A still more interesting point is that the 
antheridia both of Woodsia and of Diacalpe have a divided lid-cell, which 
is the condition shown by the Cyatheaceae, while the ‘ Polypodiaceae ’ have 
the lid-cell undivided. When these separate and apparently immaterial 
features of correspondence are put in relation to the characters of the 
sporophyte, which also indicate a Cyatheoid affinity for these Ferns, the 
evidence of such a relation appears to be very strong indeed. Woodsia 
may in fact be held to be a boreal and alpine type, derived from, but closely 
connected with, the Cyatheoid stock. In relation to its less favourable 
habitat we may note the small size of the plants themselves, and the small 
number of sporangia in the sorus. The latter fact carries with it the flattened 
receptacle. But still the basipetal sequence characteristic of the Cyatheaceae 
is retained. 
Hypoderris , R. Br. 
Hypoderris is a genus founded by Robert Brown in 1830. Mettenius 
included it in the genus Woodsia ( £ Fil. Hort. Lips. ’, 1856, p. 98), from which 
it is, however, properly separated by its habit, and by the copious anastomosis 
of the veins. It is represented by three species, of which the best known 
is H. Brownii , J. Sm., a Fern which grows upon damp and shaded rocks in 
the Antilles. The rhizome is creeping, and bears solitary leaves right and 
left, while leaves and axis are invested by soft brown scales. The leaf is 
broadly lanceolate, with two lateral lobes at its base, which are variable in 
their proportion to the central lobe. The venation is reticulate, and the 
numerous sori, with basal indusium, are ‘ inserted in lines or series parallel 
with the primary veins upon the confluent angles of the reticulate veinlets ’ 
(Hooker, £ Sp. Fil.,’ vol. i, p. 57). The general habit and appearance 
resembles that of Aspidium trifoliatum , while a comparison may also be 
drawn as regards habit with another shade-loving Fern, viz. Kaulfussia 
aesculifolia. As in the latter Fern, the sori of Hypoderris show frequent 
and various examples of fission (compare £ Land Flora’, Fig. 381). 
The vascular system of the rhizome of Hypoderris has been examined 
by Schlumberger (‘ Flora ’, 1911, p. 409, and Fig. 14, 5 ). He found that it is 
traversed by a dictyostele, with large leaf-gaps and additional £ perforations ’. 
Four vascular strands pass from each leaf-base to the subtending foliar gap, 
while the upper and under strands between the laterally placed leaf-gaps 
show wide-meshed perforations. But Schlumberger s account leaves open 
the relation between the four-stranded leaf-trace of Hypoderris and the 
two-stranded trace of related Ferns. I have examined the vascular system 
