Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/511

 March 9, 1870.

John Alleyne Bosworth, Esq., of Humberston, Leicestershire; Robert Erskine Brown, Esq., of Wass, Oswaldkirk, Yorkshire ; Major E. H. Sladen, Madras Staff Corps, Church Road, Upper Norwood; and Henry King Spark, Esq., Greenbank, Darlington, were elected Bellows of the Society.

The following communications were read : —

1. On the Structure of a Bern-stem from the Lower Eocene of Herne Bay, and on its Allies, Recent and Fossil. By Wm. Carruthers, Esq., F.L.S., F.G.S., British Museum.

[Plates XXIV. & XXV.]

The Royal Bern (Osmunda regalis, Linn.) is the noblest and most striking of our British ferns. The tuft of fronds under favourable circumstances attains a height of nearly 12 feet, and the erect stem is sometimes more than 2 feet long. The stem is perennial, growing in tufts, formed by the repeated dichotomous division of the terminal bud ; the whole is matted together by a, large mass of adventitious wiry roots. The different stems are stout and firm, and densely covered with the permanent bases of the petioles. It is found in wet, springy, or boggy places all over Britain, and is indeed generally distributed over the northern temperate zone. With one other genus, Todea, it forms a small but well-marked natural group of ferns, the Osmundaceoe.

I have determined the existence of Osmunda regalis in the Norwich Forest-bed from large specimens collected by the Rev. J. Gunn. It is common in the newer submerged forests, having maintained its ground through all the changes that have taken place.

Three closely allied forms have been found in the later Tertiary strata ; the oldest was obtained from a bed at the base of the Miocene period. I have now to add a fourth from the Bower Eocene at Herne Bay.

This species is based upon a portion of a stem in the collection of George Dowker, Esq., F.G.S. It is somewhat unequally weathered and water-worn, one of its sides being rubbed nearer to the centre than the other. The whole of the tissues are replaced by silica, and this in so perfect a manner that the most delicate structures are exquisitely preserved.

Externally the specimen exhibits the roundish petioles, irregularly broken, and marked with a single crescentic vascular bundle. Numerous adventitious roots separate the petioles from each other.

In section the stem is found to have the following structure. Near one side, from the unequal wearing of the specimen, is the slender true stem : this is composed of a white parenchymatous medulla, a narrow scalariform cylinder, and a parenchymatous cortical layer. The parenchyma of the medulla consists of roundish thin- walled cells. The slender vascular cylinder is repeatedly interrupted by the long slender meshes, from the margin of which proceed the vascular bundles that supplied the fronds. These meshes