229 
Weiss . — A Stigmaria with Centripetal Wood. 
from those known in the upper part of the plant, and which are associated 
with the system of reticulate tracheids not found in the stem but known to 
us in other Stigmarian axes. Their function in the extensive cortex of the 
axis cannot, I think, be that of transfusion tracheids, but rather that of 
water-storage. 
It might be thought that this is not a function likely to be required by 
a plant rooted, as far as we know, in a marsh ; but we know that many 
plants growing in fresh-water marshes — and still more so in salt marshes 
— are of xerophytic habit. It must also be remembered that the Lepido- 
dendraceae show certain xerophytic characters, and the Stigmarian rootlets 
were possibly not very efficient organs for rapid absorption, so that a means 
of storing water at the base of the stem may have been of some service to 
the plant in regulating the water supply during certain periods. 
That such a tissue occurred in some other forms of Stigmaria , as 
shown by Renault, would, I think, indicate that it is no individual peculiarity 
of this species, but that it serves some more or less important function of 
this part of the plant. 
In conclusion I should like to mention that, besides the similar 
Stigmarias referred to above as in Dr. Scott’s collection, there are one 
or two other axes, both among Dr. Scott’s preparations and among my own, 
which seem to be of Stigmarian nature, though possessing centripetal wood. 
The evidence in support of their Stigmarian character is, however, still 
insufficient, and I have therefore left them out of consideration for the 
present. 
Bibliography. 
Bernard, C. H. (’04). Le bois centripete dans les feuilles des Coniferes. Beihefte zum Botanischen 
Centralblatt, Band xvii, Heft 2, 1964. 
Boodle, L. A. (’04). Secondary Tracheids in Psilotuni. New Phytologist, 1904, and Annals of 
Botany, vol. xviii, 1904. 
Ford, Sibille O. (’04). The Anatomy of Psilotum. Annals of Botany, vol. xviii, 1904. 
Goldenberg, F. (’58). Flora saraepontana fossilis, 1858. 
Grand’Eury* M. (’77). Flore carbonifere du d^partement de la Loire* Mdmoires de l’Academie 
des Sciences, tome xxiv, 1877. 
Renault, M. B. (’88). Etudes sur les Stigmaria. Annales des Sciences gdologiques, tome xii, 1. 
(’93)* Etudes sur les gites mineraux de la France. Bassin Houillier et Permien 
d’Autun et d’Epinac, 1893-96. 
Scott, D. H* (’02). The Old Wood and the New. New Phytologist, vol. i, 1902. 
Seward, A. C., and A. W. Hill (’99). On the structure and affinities of a Lepidodendroid stem 
from the calciferous sandstone of Dalmeny, Scotland, possibly identical with Lepidophloios 
Harcourtii. Trans. Royal Society of Edinburgh, vol. xxxix, 1900. 
Solms-Laubach, Count FI. (’94). Ober Stigmariopsis. Palaeontologische Abhandlungen, 
Bd. ii, Heft 5, 1894. 
