344 Notes and Comments. 
the roots and air-dried. A digest of the results obtained was 
given. ; 
A PALHOZOIC FERN AND ITS RELATIONSHIPS. 
In a paper by Dr. D. H. Scott it was pointed out that the 
simpler Paleozoic Ferns (Primofilices of Mr. Arber, Coenop- 
terideee of Professor Seward) have received much attention of 
late, especially in the fine memoirs of M. Paul Bertrand. 
Zygopteris Grayt, a species founded by Williamson in 1888, on 
somewhat imperfect material, occurs both in roof and seam 
nodules of Lancashire coalbeds, but is very rare. Besides 
the specimens described by Williamson, there is a much better 
one, the sections of which are partly in his collection ; this has 
been figured by the author in 1900, by M. Paul Bertrand in 
1g09g, and by Mr. Kidston ,in 1910, but never adequately. 
Last year a fine series of sections of an entirely new specimen 
from Shore Littleborough was received from Mr. Lomax. The 
new specimen shews the general characters of the Z. Grayi type ; 
a five-rayed stellate stele, the corresponding 2 phyllotaxis, 
leaf-trace bundles with axillary shoots, scale-leaves or aphlebiz, 
and adventitious roots. The characteristic internal xylem, 
consisting of narrow tracheides embedded in parenchyma, 
is particularly well shown, both in the main stem and in the 
axillary stele. This specimen affords clear evidence that it 
belongs to the genus Ankyropteris, as defined by P. Bertrand. 
The leaf-trace and foliar bundle show perfectly the peripheral 
loops of small-celled xylem characteristic of Ankyropteris. The 
loops begin to be differentiated long before the leaf-trace 
separates from the stele. This confirms P. Bertrand’s own 
view ; he found periphal loops in the best Williamson specimen, 
where, however, they are very obscure compared with those 
in the Shore plant. 
BROWN SEAWEEDS OF SALT MARSHES. 
Miss Sarah M. Baker, in referring to this subject, stated that 
the capability of giving rise to marsh forms seems to be shared 
by all the brown seaweeds inhabiting the upper parts of rocky 
shores. Pelvetia canaliculata, Fucus spiralis, Ascophyllum 
nodosum, and Fucus vesiculosus, all show marsh varieties or 
species. The reason that Fucus serratus and F. ceranoides 
have no representatives in the marsh habitat is probably their 
intolerance of desiccation. The physical and chemical en- 
vironment factors on the marsh being much more complex 
and varied than on a rocky shore, one would expect a corres- 
ponding variation in the structure of its plant. The most 
marked characteristics of the common marsh species are a 
great tendency to spiral twisting or curling of the thallus— 
and vegetative reproduction. That this latter feature is not 
directly caused by the marsh habitat is shewn by exceptional 
Naturalist, 
